The GPlates Geological Information Model (GPGIM)

Technical Reference Document

GPGIM Version: 1.6.0327

The document you are reading is a technical reference for how GPlates uses and stores data according to its information model. It is a direct transliteration of the XML file that GPlates uses internally to describe that information model. It is intended to be an aid for those editing the GPGIM XML file and anyone creating software that produces or consumes GPML or other GPlates-compatible data.

Table of Contents:-

Property Type List

A list of all the types of property value that GPlates understands, including Enumerations (a set of string values defining categorical values), and Native Properties (types of complex or "structural" values that are built in to GPlates).

gpml:AbsoluteReferenceFrameEnumeration

Description:-
Type of absolute reference frame.
Possible values:-
Used by properties:-
gpml:absoluteReferenceFrame

gpml:ContinentalBoundaryCrustEnumeration

Description:-
The type of the crust contained within a boundary.
Possible values:-
Used by properties:-
gpml:crust

gpml:ContinentalBoundaryEdgeEnumeration

Description:-
Enumerates whether a continental boundary is the inner or outer boundary in the broad area of change between continental and oceanic crust.
Possible values:-
Used by properties:-
gpml:edge

gpml:ContinentalBoundarySideEnumeration

Description:-
Assuming there is a suitable centerLineOf supplied, and understanding that the order of points in the line matters, we can establish a "Left" side and a "Right" side to the .centerLineOf. this property indicates which direction leads to the continental crust.
Possible values:-
Used by properties:-
gpml:side

gpml:DipSideEnumeration

Description:-
The side of the line that the 'dip' is on, giving a hint at what the plane of the surface looks like.
Possible values:-
Used by properties:-
gpml:dipSide

gpml:DipSlipEnumeration

Description:-
The motion along the 'dip', or cross-section line of the Fault.
Possible values:-
Used by properties:-
gpml:dipSlip

gpml:FoldPlaneAnnotationEnumeration

Description:-
Type of annotation for a FoldPlane. Appears as symbols along the line of the fold.
Possible values:-
Used by properties:-
gpml:foldAnnotation

gpml:ReconstructionMethodEnumeration

Description:-
The method used to reconstruct feature geometry to paleo times.
Possible values:-
Used by properties:-
gpml:reconstructionMethod

gpml:SlipComponentEnumeration

Description:-
For Faults with both Dip-Slip and Strike-Slip motion (sometimes termed "Oblique Slip"), this property indicates which of Dip-Slip or Strike-Slip is the primary component of the motion, if any.
Possible values:-
Used by properties:-
gpml:primarySlipComponent

gpml:StrikeSlipEnumeration

Description:-
The motion along the 'strike', or map-view line of the Fault.
Possible values:-
Used by properties:-
gpml:motion, gpml:strikeSlip

gpml:SubductionPolarityEnumeration

Description:-
Indicates which side of the line (when following the vertices in order) that the over-riding plate is on. The subducting plate will be on the opposite side. .subductingSlab is an enumeration: Assuming there is a suitable centerLineOf supplied, and understanding that the order of points in the line matters, we can establish a "left" side and a "right" side to the .centerLineOf. this property indicates which of those "left" and "right" sides the over-riding plate is on. The subducting plate will be on the opposite side.
Possible values:-
Used by properties:-
gpml:subductionPolarity

xsi:boolean (Native Property Type)

Description:-
A true/false boolean.
Used by properties:-
gpml:isActive, gpml:slabFlatLying

xsi:double (Native Property Type)

Description:-
A double-precision floating-point number.
Used by properties:-
gpml:averageAge, gpml:averageDeclination, gpml:averageInclination, gpml:coreRecovered, gpml:depthToBasement, gpml:networkMaxEdge, gpml:networkShapeFactor, gpml:polarityChronOffset, gpml:poleA95, gpml:poleDm, gpml:poleDp, gpml:sedimentThickness, gpml:slabFlatLyingDepth, gpml:spreadingAsymmetry, gpml:subductionZoneAge, gpml:subductionZoneConvergence, gpml:subductionZoneDeepDip, gpml:subductionZoneDepth, gpml:waterDepth

xsi:integer (Native Property Type)

Description:-
A signed integer number.
Used by properties:-
gpml:subductionZoneSystemOrder

xsi:string (Native Property Type)

Description:-
An arbitrary string of characters.
Used by properties:-
gpml:coreData, gpml:dataSeries, gml:description, gpml:expedition, gpml:hole, gpml:initialReportVolume, gpml:logData, gml:name, gpml:program, gpml:publication, gpml:rheaFault, gpml:site, gpml:slabEdgeType, gpml:subcategory, gpml:subductionZoneSystem

gml:File (Native Property Type)

Description:-
A reference to a file in the file system.
Used by properties:-
gpml:rangeSet

gml:LineString (Native Property Type)

Description:-
A list of latitude/longitude coordinate tuples defining a polyline.
Used by properties:-
gpml:boundary, gpml:centerLineOf, gpml:outlineOf, gpml:unclassifiedGeometry

gml:MultiPoint (Native Property Type)

Description:-
A list of latitude/longitude coordinate tuples defining an unordered set of points.
Used by properties:-
gpml:centerLineOf, gpml:errorBounds, gpml:meshPoints, gpml:multiPosition, gpml:outlineOf, gpml:seedPoints, gpml:unclassifiedGeometry

gml:OrientableCurve (Native Property Type)

Description:-
A list of latitude/longitude coordinate tuples defining a polyline and a '+' or '-' orientation.
Used by properties:-
gpml:boundary, gpml:centerLineOf, gpml:errorBounds, gpml:outlineOf, gpml:unclassifiedGeometry

gml:Point (Native Property Type)

Description:-
A single latitude/longitude coordinate tuple defining a point.
Used by properties:-
gpml:averageSampleSitePosition, gpml:centerLineOf, gpml:centre, gpml:errorBounds, gpml:outlineOf, gpml:polePosition, gpml:position, gpml:seedPoints, gpml:unclassifiedGeometry

gml:Polygon (Native Property Type)

Description:-
A list of latitude/longitude coordinate tuples defining a closed polyline exterior and zero or more lists of latitude/longitude coordinate tuples each defining an interior hole region.
Comments:-

Currently interiors holes are not yet supported in GPlates.

Used by properties:-
gpml:boundary, gpml:centerLineOf, gpml:errorBounds, gpml:outlineOf, gpml:unclassifiedGeometry

gml:RectifiedGrid (Native Property Type)

Description:-
A grid for which there is an affine transformation between the grid coordinates and the coordinates of an external coordinate reference system. Defined by a grid origin and two offset vectors.
Used by properties:-
gpml:domainSet

gml:TimeInstant (Native Property Type)

Description:-
Represents an identifiable position in time.
Used by properties:-

gml:TimePeriod (Native Property Type)

Description:-
The period of time the feature is in existence.
Comments:-

Consists of two variables, "begin" and "end", which are the points in time (in millions of years ago or Ma) in which the feature came in and out of existence respectively.

"Begin" and "end" can also be set to "Distant Past" and "Distant Future" respectively.

Used by properties:-
gml:validTime

gpml:Array (Native Property Type)

Description:-
A sequence of elements of a specified template type.
Used by properties:-
gpml:times

gpml:FeatureReference (Native Property Type)

Description:-
Reference to a remote feature.
Used by properties:-
gpml:conjugate, gpml:evidence, gpml:islandArc, gpml:leftUnit, gpml:pick, gpml:rightUnit, gpml:shipTrack, gpml:trail, gpml:truncatedSection

gpml:FeatureSnapshotReference (Native Property Type)

Description:-
Reference to a specific version of a remote feature.
Used by properties:-

gpml:FiniteRotation (Native Property Type)

Description:-
A rotation which maps a position on the surface of the globe to another position on the surface of the globe.
Used by properties:-
gpml:totalReconstructionPole

gpml:HotSpotTrailMark (Native Property Type)

Description:-
The marks that define the HotSpotTrail.
Comments:-

You can draw the line through them, but it is more accurate to store the individual points and their positions in space and time.

In the Rotation hierarchy, will depend on a Platelike AbsoluteReferenceFrame.

Used by properties:-
gpml:mark

gpml:KeyValueDictionary (Native Property Type)

Description:-
A dictionary mapping arbitrary key names to values for data which has been imported from shapefiles.
Used by properties:-
gpml:dataDictionary, gpml:mprsAttributes, gpml:shapefileAttributes

gpml:measure (Native Property Type)

Description:-
Extends double and adds a uom attribute indicating the units used.
Used by properties:-
gpml:angularRadius, gpml:dipAngle

gpml:OldPlatesHeader (Native Property Type)

Description:-
Metadata inherited from imported PLATES data files.
Comments:-

This is no longer editable within the GPlates UI to prevent data getting out of sync.

Used by properties:-
gpml:oldPlatesHeader

gpml:plateId (Native Property Type)

Description:-
A unique Id for a group of features that rotate in unison.
Used by properties:-
gpml:conjugatePlateId, gpml:fixedReferenceFrame, gpml:leftPlate, gpml:movingReferenceFrame, gpml:reconstructionPlateId, gpml:relativePlate, gpml:rightPlate

gpml:PolarityChronId (Native Property Type)

Description:-
A structural type holding the identifier of an Isochron or MagneticAnomalyIdentification.
Comments:-

The identifier used for magnetic picks evolved to be a combination of letters and numbers, of the form (C|M)[number][combination of letters].

The first letter indicates Cenozoic or Mesozoic era, followed by a number indicating the chron's position in the sequence. However, the early measurements of isochrons were not very high resolution, and many smaller polarity reversals were missed, only to be discovered later as techniques improved. Rather than renumbering everything as new isochrons were discovered, letters from a-z were added after the number, so M14a refers to the first sub-chron located inside the 14th major chron, and if a polarity reversal were located inside that, it would be named M14aa, and so on.

This would result in names such as C34ad, which translates to a Cenozoic isochron, major region 34, sub region a, sub region d.

Used by properties:-
gpml:polarityChronId

gpml:RasterBandNames (Native Property Type)

Description:-
The names of the bands in a raster.
Used by properties:-
gpml:bandNames

gpml:revisionId (Native Property Type)

Description:-
Unique identifiers used for the specific revisions of gpml:AbstractFeatures.
Comments:-

They must be unique for each revision, generated at revision creation time.

The final revisionId string should be restricted to the characters that are acceptable for XML Ids: http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#Id

Used by properties:-
gpml:supersededRevision

gpml:ScalarField3DFile (Native Property Type)

Description:-
The 3D scalar field file generated by GPlates during import.
Used by properties:-
gpml:file

gpml:StringList (Native Property Type)

Description:-
A list of strings.
Used by properties:-
gpml:locationNames

gpml:TopologicalLine (Native Property Type)

Description:-
A dynamic polyline formed by topological references to regular geometries of other features.
Used by properties:-
gpml:centerLineOf, gpml:unclassifiedGeometry

gpml:TopologicalNetwork (Native Property Type)

Description:-
A dynamic triangulation consisting of a boundary and optional interior constraints formed by topological references to regular geometries and topological lines of other features.
Used by properties:-
gpml:network

gpml:TopologicalPolygon (Native Property Type)

Description:-
A dynamic polygon formed by topological references to regular geometries and topological lines of other features.
Used by properties:-
gpml:boundary, gpml:errorBounds, gpml:outlineOf, gpml:unclassifiedGeometry

gpml:GpmlMetadata (Native Property Type)

Description:-
The metadata for feature collection.
Used by properties:-
gpml:metadata

Property List

The definition of every possible property that can be included by features - what the property name is, how often it can appear in a single feature, and what type of value is supported.

gpml:absoluteReferenceFrame

Description:-
Type of absolute reference frame.
Used by features:-
gpml:AbsoluteReferenceFrame

gpml:angularRadius

Description:-
Angular radius.
Comments:-

This is currently used for small circle radii.

Used by features:-
gpml:SmallCircle

gpml:averageAge

Description:-
Average magnetisation age (GeologicalTime of magnetisation) based on multiple sites.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:averageDeclination

Description:-
Average direction in stratigraphic coordinates, declination.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:averageInclination

Description:-
Average direction in stratigraphic coordinates, inclination.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:averageSampleSitePosition

Description:-
Average sample-site position (based on multiple sites).
Used by features:-
gpml:VirtualGeomagneticPole

gpml:bandNames

Description:-
The names of the raster bands in a raster.
Used by features:-
gpml:Raster

gpml:boundary - Boundary

Description:-
A static or topological (plate) boundary depending on the feature type.
Used by features:-
gpml:ClosedContinentalBoundary, gpml:ClosedPlateBoundary, gpml:TopologicalClosedPlateBoundary

gpml:centerLineOf - Centre line

Description:-
The central line defining the feature's geometry.
Comments:-

Note that the name is based on GML's gml:centerLineOf, and as such is using the American spelling of "center".

Used by features:-
gpml:AbstractGeologicalPlane, gpml:AseismicRidge, gpml:Coastline, gpml:ContinentalCrust, gpml:OceanicCrust, gpml:GeologicalLineation, gpml:InferredPaleoBoundary, gpml:Isochron, gpml:MagneticAnomalyShipTrack, gpml:OldPlatesGridMark, gpml:PoliticalBoundary, gpml:PseudoFault, gpml:SlabEdge, gpml:Suture, gpml:TectonicSection

gpml:centre

Description:-
Centre of a small circle.
Comments:-

Note that the name is using Australian / Canadian / NZ / UK English spelling of "centre". This is inconsistent with what we've done above with g(p)ml:centerLineOf. Great. I don't know how to fix this, it's a pretty terrible situation. --jclark 20150113

Used by features:-
gpml:SmallCircle

gpml:conjugate

Description:-
A reference to the 'pair' or 'twin' of the isochron.
Comments:-

Due to Isochrons getting split into pieces in PLATES data, it must support more than one conjugate on the other side of the MOR.

Used by features:-
gpml:Isochron

gpml:conjugatePlateId

Description:-
A reference to the plate Id that has the 'pair' or 'twin' of the feature.
Comments:-

The plate Id is a general-purpose plate Id or specific plate Id for motion of a cluster of Features.

Used by features:-
gpml:Isochron, gpml:TectonicSection

gpml:coreData

Description:-
A URL for Core Data
Used by features:-
gpml:OceanDrillSite

gpml:coreRecovered

Description:-
Length of Core Recovered in meters.
Used by features:-
gpml:OceanDrillSite

gpml:crust

Description:-
The type of the crust contained within a boundary.
Used by features:-
gpml:ClosedContinentalBoundary

gpml:dataDictionary

Description:-
A set of data, stored as KeyValueDictionary: 'key=value' pairs: key1=value1, key2=value2, key3=value3, etc.
Used by features:-
gpml:OceanDrillSite

gpml:dataSeries

Description:-
A series of data, as 'datum=value' pairs in simple text string form: 'data1=value1, datum2=value2, dataum3=value3', etc.
Comments:-

This property is a qucik way to capture user data for depth or time series data. For example, measured values (such as water density) at various depths for a single sample site: 'depth1=value1, depth2=value2, depth3=value3'.

Used by features:-
gpml:OceanDrillSite

gpml:depthToBasement

Description:-
Depth to basement rock at the sample site.
Used by features:-
gpml:OceanDrillSite

gml:description

Description:-
A description of the feature.
Comments:-

A 'hidden but useful' property inherited from GML.

Used by features:-
gml:AbstractFeature

gpml:dipAngle

Description:-
Used to describe the angle a surface "dips" from the horizontal, usually in degrees.
Comments:-

The complete orientation of the plane is the strike (stored in the centerLineOf geometry property), the dip angle (stored in this property), and the dip direction (stored in the dipSide property).

This property is optional. If not present, it indicates that there is no information about the dip available. The property is unspecified or indeterminate.

Used by features:-
gpml:AbstractGeologicalPlane, gpml:TopologicalSlabBoundary

gpml:dipSide

Description:-
Used to specify the dip direction of the plane.
Comments:-

The complete orientation of the plane is the strike (stored in the centerLineOf geometry property), the dip angle (stored in the dipAngle property), and the dip direction (stored in this property).

Used by features:-
gpml:AbstractGeologicalPlane

gpml:dipSlip

Description:-
The motion along the 'dip', or cross-section line of the Fault.
Used by features:-
gpml:Fault

gpml:domainSet

Description:-
The region-of-interest of a coverage or raster on which the corresponding 'gpml:rangeSet' is based.
Comments:-

This is currently only used for rasters.

Used by features:-
gpml:Raster

gpml:edge

Description:-
Enumerates whether a continental boundary is the inner or outer boundary in the broad area of change between continental and oceanic crust.
Used by features:-
gpml:ClosedContinentalBoundary, gpml:PassiveContinentalBoundary

gpml:errorBounds - Error boundary

Description:-
An optional error boundary for the feature.
Comments:-

Note that we can use LineStrings or Polygons or a combination of both.

Used by features:-
gpml:HotSpotTrail, gpml:InferredPaleoBoundary

gpml:evidence

Description:-
Features listed as evidence of the HotSpotTrail.
Comments:-

As a convenience, you may also include references to other gpml:Features here, as the 'evidence' of the HotSpotTrail. These can be the physical features that indicate the path the HotSpot took- Volcanoes, Seamounts, maybe even AseismicRidges - we have to be pretty forgiving with what features the user wants to associate with the HotSpotTrail.

Used by features:-
gpml:HotSpotTrail

gpml:expedition

Description:-
The name or identifer of the Expedition related to this feature
Used by features:-
gpml:OceanDrillSite

gpml:file

Description:-
Type of annotation for a FoldPlane. Appears as symbols along the line of the fold.
Used by features:-
gpml:ScalarField3D

gpml:foldAnnotation

Description:-
Type of annotation for a FoldPlane. Appears as symbols along the line of the fold.
Used by features:-
gpml:FoldPlane

gpml:fixedReferenceFrame

Description:-
The plate Id for which motion is treated as 'fixed'.
Used by features:-
gpml:TotalReconstructionSequence

gpml:hole

Description:-
The identifer for the drill hole
Used by features:-
gpml:OceanDrillSite

gpml:initialReportVolume

Description:-
URL for the drill hole data
Used by features:-
gpml:OceanDrillSite

gpml:isActive

Description:-
Time-dependent boolean indicates when the feature is active over time.
Comments:-

In the case of MidOceanRidge and ContinentalRift, isActive should be "True" if the ridge is actively spreading, and "False" otherwise.

In the case of IslandArc, isActive is "True" if the IslandArc is in the process of being created via subduction, and "False" otherwise.

Used by features:-
gpml:IslandArc, gpml:MidOceanRidge, gpml:SubductionZone

gpml:islandArc

Description:-
Multiple small island arcs potentially forming part of a large subduction zone.
Used by features:-
gpml:SubductionZone

gpml:leftPlate

Description:-
Annotation property describing the plate on the "left" side of the feature.
Comments:-

Not to be used for reconstruction purposes, as these properties would be an imprecise representation of the crust on each side in many cases. Primarily of interest to the MidOceanRidge feature, where it is used for the purpose of a richer description.

Not a time-dependent property because, for MidOceanRidge at any rate, that's insanity. A MidOceanRidge -generates- crust. For other boundary features, like SubductionZone, this property is only really used as annotation, (i.e. "this SZ is mostly consuming plate 541") and doesn't need to be over-complex.

This property doesn't support multiple plateIds per side for similar reasons to the ones above; in the case of MidOceanRidge, the usefuless of this property hinges on the potential to e.g. interpolate between both sides of the MOR and determine velocity. If more than one plateId per side were supported, topology would have to be taken into consideration, and pieces would have to move at different rates - and so the MOR would have to be broken up into segments, PLATES style. Perhaps when we get segmented MORs in the next release GPGIM, we can consider these extra possibilities. Until then, there's really no point in making this more complex than it needs to be.

Used by features:-
gpml:Flowline, gpml:TectonicSection

gpml:leftUnit

Description:-
Defines what is on the "Left" side of the contact, using an AbstractRockUnit.
Comments:-

Assuming there is a suitable centerLineOf supplied, and understanding that the order of points in the line matters, we can establish a "Left" and "Right" side of the centerLine.

Particular implementations of AbstractRockUnit can include BasicRockUnit for simple free-text descriptions plus an extent, or more complex rock unit definitions.

Used by features:-
gpml:AbstractGeologicalContact

gpml:locationNames - Location names

Description:-
List of location, dredge or drill site names.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:logData

Description:-
A URL for Log Data
Used by features:-
gpml:OceanDrillSite

gpml:mark

Description:-
Forms a table of hotspot position and age, using HotSpotTrailMark to represent each row.
Used by features:-
gpml:HotSpotTrail

gpml:meshPoints

Description:-
Global positions to calculate plate velocities at.
Used by features:-
gpml:MeshNode

gpml:metadata

Description:-
The metadata for feature collection.
Used by features:-
gpml:FeatureCollectionMetadata

gpml:motion

Description:-
The motion along the 'strike', or map-view line of the Transform.
Used by features:-
gpml:Transform

gpml:movingReferenceFrame

Description:-
The 'conjugate' or 'moving' plate Id.
Used by features:-
gpml:TotalReconstructionSequence

gpml:mprsAttributes

Description:-
Moving Plate Rotation Sequence attributes.
Used by features:-
gpml:TotalReconstructionSequence

gpml:multiPosition - Multiple positions

Description:-
When a feature’s geometry is described as a multiple points, it is appropriate to use the MultiPoint geometry.
Used by features:-
gpml:ContinentalCrust, gpml:OceanicCrust, gpml:DisplacementPoint, gpml:HotSpot, gpml:MagneticAnomalyIdentification, gpml:PolygonCentroidPoint, gpml:StrainMarker

gml:name

Description:-
A descriptive name of the feature.
Comments:-

More than one gml:name can be assigned, the distinction between two names being handled by the 'codeSpace=' attribute of gml:name.

Used by features:-
gml:AbstractFeature

gpml:network

Description:-
A topological network used to define a deforming region.
Used by features:-
gpml:TopologicalNetwork

gpml:networkMaxEdge

Description:-
Another parameter to control triangulation quality in a topological network.
Comments:-

This is a Computational Geometry Algorithms Library (CGAL) parameter.

Used by features:-
gpml:TopologicalNetwork

gpml:networkShapeFactor

Description:-
Determines the shape (or closeness to being equilateral) the triangles in a topological network triangulation should be.
Comments:-

This is a Computational Geometry Algorithms Library (CGAL) parameter.

Used by features:-
gpml:TopologicalNetwork

gpml:oldPlatesHeader

Description:-
Metadata imported from a PLATES data file.
Comments:-

Since a Feature in GPML will often correspond to a PLATES polyline (if a PLATES file was the original source of data), we include an optional reference to a Plates-compatible header object. This is used to keep metadata around if we import from a PLATES data file.

Used by features:-
gpml:AbstractFeature

gpml:outlineOf - Outline

Description:-
Geometry specifying a closed or partial outline.
Used by features:-
gpml:AbstractField, gpml:AseismicRidge, gpml:BasicRockUnit, gpml:Basin, gpml:ContinentalCrust, gpml:OceanicCrust, gpml:ContinentalFragment, gpml:Craton, gpml:ExtendedContinentalCrust, gpml:IslandArc, gpml:LargeIgneousProvince, gpml:OceanDrillSite, gpml:Ophiolite, gpml:Pluton, gpml:PoliticalBoundary, gpml:Seamount, gpml:Suture, gpml:TectonicSection, gpml:TransitionalCrust, gpml:Volcano

gpml:pick

Description:-
An (optional) reference to the MagneticAnomalyIdentification s recorded from this ship track data.
Comments:-

A feature reference because these data sometimes exist independently of each other, so they should both be gpml:Features.

Optional because you may get a bunch of picks all in close proximity and things stop being clear, odd datasets, etc.

Used by features:-
gpml:MagneticAnomalyShipTrack

gpml:polarityChronId

Description:-
The string name of the polarity chron based on the geomagnetic reversal timescale.
Comments:-

This identifier indicates which Polarity Chron this pick is linked to: other picks on different ship-tracks will share this Id if they belong to the same Chron. e.g. "C34b".

Note that we want this to be unique for each Chron, so the tradition of packing extra info like the 'young/old' value onto the end of the Id ("C34o0.2") is discouraged; polarityChronOffset can be used to store the young/old offset, and any miscellaneous extra information can go in metadata, gml:name, gml:description, or gpml:subcategory as appropriate.

It is called "polarity chron" because it is the 'chron' of all positions sharing the same polarity.

Used by features:-
gpml:FractureZoneIdentification, gpml:Isochron, gpml:MagneticAnomalyIdentification

gpml:polarityChronOffset

Description:-
Specifies the location on the polarity chron, from youngest to oldest.
Comments:-

A number from 0.0 to 1.0, indicating the proportion from 'young' to 'old'; 0.0 = young, 1.0 = old; This property stores the offset of this pick's chron position compared to the synthetic chron.

Used by features:-
gpml:FractureZoneIdentification, gpml:MagneticAnomalyIdentification

gpml:poleA95

Description:-
Error circle based on uncertainty of the average of pole positions.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:poleDm

Description:-
VGP uncertainty, meridian.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:poleDp

Description:-
VGP uncertainty, parallel latitude.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:polePosition

Description:-
Virtual geomagnetic pole.
Used by features:-
gpml:VirtualGeomagneticPole

gpml:position - Position

Description:-
When a feature’s geometry is described as a point, it is appropriate to use the Point geometry.
Used by features:-
gpml:BasicRockUnit, gpml:ContinentalCrust, gpml:OceanicCrust, gpml:DisplacementPoint, gpml:FractureZoneIdentification, gpml:HotSpot, gpml:MagneticAnomalyIdentification, gpml:NavdatSample, gpml:OceanDrillSite, gpml:Ophiolite, gpml:Pluton, gpml:PolygonCentroidPoint, gpml:Seamount, gpml:StrainMarker, gpml:Volcano

gpml:primarySlipComponent

Description:-
For Faults with both Dip-Slip and Strike-Slip motion (sometimes termed "Oblique Slip"), this property indicates which of Dip-Slip or Strike-Slip is the primary component of the motion, if any.
Used by features:-
gpml:Fault

gpml:program

Description:-
An identifer for the scientific Program related to this feature
Used by features:-
gpml:OceanDrillSite

gpml:publication

Description:-
An identifer for publications related to this feature
Used by features:-
gpml:OceanDrillSite

gpml:rangeSet

Description:-
The coverage or raster values at the corresponding 'gpml:domainSet' region-of-interest.
Used by features:-
gpml:Raster

gpml:reconstructionMethod

Description:-
The method used to reconstruct feature geometry to paleo times.
Used by features:-
gpml:Flowline, gpml:MotionPath, gpml:TectonicSection

gpml:reconstructionPlateId

Description:-
The plateID that will be used for reconstruction purposes.
Used by features:-
gpml:ReconstructableFeature, gpml:TopologicalClosedPlateBoundary, gpml:TopologicalNetwork

gpml:relativePlate

Description:-
The plate that something is relative to.
Comments:-

This is currently used in MotionPath features as the plate that the motion is relative to.

Used by features:-
gpml:MotionPath

gpml:rheaFault

Description:-
Rhea fault.
Used by features:-
gpml:SubductionZone

gpml:rightPlate

Description:-
Annotation property describing the plate on the "right" side of the feature.
Comments:-

Not to be used for reconstruction purposes, as these properties would be an imprecise representation of the crust on each side in many cases. Primarily of interest to the MidOceanRidge feature, where it is used for the purpose of a richer description.

Not a time-dependent property because, for MidOceanRidge at any rate, that's insanity. A MidOceanRidge -generates- crust. For other boundary features, like SubductionZone, this property is only really used as annotation, (i.e. "this SZ is mostly consuming plate 541") and doesn't need to be over-complex.

This property doesn't support multiple plateIds per side for similar reasons to the ones above; in the case of MidOceanRidge, the usefuless of this property hinges on the potential to e.g. interpolate between both sides of the MOR and determine velocity. If more than one plateId per side were supported, topology would have to be taken into consideration, and pieces would have to move at different rates - and so the MOR would have to be broken up into segments, PLATES style. Perhaps when we get segmented MORs in the next release GPGIM, we can consider these extra possibilities. Until then, there's really no point in making this more complex than it needs to be.

Used by features:-
gpml:Flowline, gpml:TectonicSection

gpml:rightUnit

Description:-
Defines what is on the "Right" side of the contact, using an AbstractRockUnit.
Comments:-

Assuming there is a suitable centerLineOf supplied, and understanding that the order of points in the line matters, we can establish a "Left" and "Right" side of the centerLine.

Particular implementations of AbstractRockUnit can include BasicRockUnit for simple free-text descriptions plus an extent, or more complex rock unit definitions.

Used by features:-
gpml:AbstractGeologicalContact

gpml:sedimentThickness

Description:-
Sediment Thickness at the sample site.
Used by features:-
gpml:OceanDrillSite

gpml:seedPoints

Description:-
The points from which the Flowline and MotionPath time-paths are generated.
Used by features:-
gpml:Flowline, gpml:MotionPath

gpml:shapefileAttributes

Description:-
Attribute data imported from a Shapefile data file.
Comments:-

As a large amount of data may be imported from Shapefiles, and there is not always an obvious way to map from (arbitrary) shapefile attributes to GPML property names, the user may need to set up a mapping that defines which shapefile attributes should be mapped, and the GPML property they are mapped to.

For example, the user may have a data set with "PLATEID" and "NAME" shapefile properties - these need to be mapped to the Feature's gpml:reconstructionPlateId and gml:name properties. Storing the mapping is important so that data can be returned to the original shapefile attributes later.

Used by features:-
gpml:AbstractFeature

gpml:shipTrack

Description:-
Optional reference to the MagneticAnomalyShipTrack that this pick originates from.
Used by features:-
gpml:FractureZoneIdentification, gpml:MagneticAnomalyIdentification

gpml:side

Description:-
Indicates which direction leads to the continental crust.
Used by features:-
gpml:PassiveContinentalBoundary

gpml:site

Description:-
Site name for this feature
Used by features:-
gpml:OceanDrillSite

gpml:slabEdgeType

Description:-
The type of slab edge.
Used by features:-
gpml:SlabEdge, gpml:SubductionZone

gpml:slabFlatLying

Description:-
Whether the slab is flat lying or not.
Used by features:-
gpml:SlabEdge, gpml:TopologicalSlabBoundary

gpml:slabFlatLyingDepth

Description:-
The slab flat lying depth.
Used by features:-
gpml:SlabEdge, gpml:TopologicalSlabBoundary

gpml:spreadingAsymmetry

Description:-
The asymmetry of ridge spreading, in the range [-1,1], where the value 0 represents symmetric (half-stage) rotation.
Used by features:-
gpml:MidOceanRidge

gpml:strikeSlip

Description:-
The motion along the 'strike', or map-view line of the Fault.
Used by features:-
gpml:Fault

gpml:subcategory

Description:-
A free-form text string to optionally assign one or more subcategories to a feature type.
Comments:-

Every gpml:Feature can optionally have one or more subcategories assigned to it. These are free-form text strings, and behave very similarly to the gml:name property; they also possess a 'codeSpace=' attribute to indicate what convention was used when assigning this subcategory to this Feature.

Use of the .subcategory property is entirely optional, however it is useful in several situations. There are many possible subcategories of real-world:Features, and these are highly subjective, depending on scientist, dataset, and area of research. Permitting arbitrary subcategorisation in the GPGIM has two benefits. One, GPlates can to continue to treat those real-world:Features as the appropriate gpml:Feature since any subcategory must have the same properties as the parent gpml:Feature. Two, it allows the scientist to have a finer grain of control over the categorisation of those real-world:Features without messing around with XML trying to extend the GPGIM.

An example: Seamount s and Guyot s. A Guyot is a special case of Seamount with a flat top. Functionally, they are identical. A problem arises; do we create a GPGIM feature for both of them, or just use Seamount for both cases? Some scientists and datasets may not care about the distinction, and wish to treat everything as a gpml:Seamount without being forced to go over the data and classify everything. On the other hand, a "Guyot Expert" would be very interested in the distinction between the two. The .subcategory property allows you to do this, without forcing you to.

Used by features:-
gpml:AbstractFeature

gpml:subductionPolarity

Description:-
Indicates which side of the line (when following the vertices in order) that the over-riding plate is on.
Used by features:-
gpml:OrogenicBelt, gpml:SlabEdge, gpml:SubductionZone

gpml:subductionZoneAge

Description:-
Age of subduction zone.
Used by features:-
gpml:SlabEdge, gpml:SubductionZone

gpml:subductionZoneConvergence

Description:-
Convergence rate of subduction zone in cm/year.
Used by features:-
gpml:SlabEdge, gpml:SubductionZone

gpml:subductionZoneDeepDip

Description:-
Subduction zone deep dig.
Used by features:-
gpml:SlabEdge, gpml:SubductionZone

gpml:subductionZoneDepth

Description:-
Subduction zone depth.
Used by features:-
gpml:SlabEdge, gpml:SubductionZone

gpml:subductionZoneSystem

Description:-
A unique name for a collection of Subduction Zones forming a continuous system of subduction.
Used by features:-
gpml:SlabEdge, gpml:SubductionZone

gpml:subductionZoneSystemOrder

Description:-
The order where this subduction zone appears in the system (note: this is zero-based sequence)
Used by features:-
gpml:SlabEdge, gpml:SubductionZone

gpml:supersededRevision

Description:-
Lists all revisions of this feature that were superseded by this one.
Comments:-

This is a more accurate way of keeping track of the past, older revisions of a feature.

It will be purged on occasion to ensure files do not get bloated from many small changes. Newly superseded revisionId s get unshifted onto the front/head of the list, older ones are at the end/tail of the list.

A simple linear 'version number' would fail if a feature collection was concurrently modified by multiple users and then merged.

Used by features:-
gpml:AbstractFeature

gpml:times

Description:-
An array of time instants.
Comments:-

Typically used to store the time instants at which Flowline and MotionPath features output points along the time-path.

Used by features:-
gpml:Flowline, gpml:MotionPath

gpml:totalReconstructionPole

Description:-
A sequence of FiniteRotations and associated gml:TimeInstants, with FiniteRotationSlerp interpolation between them.
Used by features:-
gpml:TotalReconstructionSequence

gpml:trail

Description:-
HotSpots can be associated with zero, one, or more HotSpotTrails.
Comments:-

HotSpots can be associated with zero, one, or more HotSpotTrails. Zero because there might not be any data about the movement of the HotSpot; One will be the most common case; and Two or more for disjoint HotSpotTrails. It is a reference to a HotSpotTrail, because HotSpotTrails may be rotated independently, and should be gpml:Features in their own right.

Used by features:-
gpml:HotSpot, gpml:StrainMarker

gpml:truncatedSection

Description:-
Optional references to other Features that the user has indicated are supposed to be the same feature.
Comments:-

While GPlates will treat each individual gpml:Feature separately, it is intended as a reminder that this Feature is part of a larger whole.

A common problem in PLATES datasets is the lack of any deformable geometry. This is often hacked around by creating multiple 'features' for the same real-world thing, for example, an Isochron getting subducted might have have been 'cut up' into multiple PLATES 'IS' features, to simulate the Isochron slowly disappearing. One day, this property will be used by a magical algorithm to undo all the 'cutting up' of features done in data sets for the purpose of hacking deformable geometry into PLATES.

Used by features:-
gpml:ReconstructableFeature

gpml:unclassifiedGeometry - Unclassified / miscellaneous

Description:-
All geometry defined for the feature where the purpose is not given or is unclear.
Used by features:-
gpml:AbstractGeologicalPlane, gpml:AseismicRidge, gpml:BasicRockUnit, gpml:Basin, gpml:Coastline, gpml:ContinentalCrust, gpml:OceanicCrust, gpml:ContinentalFragment, gpml:Craton, gpml:DisplacementPoint, gpml:ExtendedContinentalCrust, gpml:GeologicalLineation, gpml:HotSpot, gpml:HotSpotTrail, gpml:InferredPaleoBoundary, gpml:IslandArc, gpml:Isochron, gpml:LargeIgneousProvince, gpml:MagneticAnomalyShipTrack, gpml:NavdatSample, gpml:OceanDrillSite, gpml:OldPlatesGridMark, gpml:Ophiolite, gpml:Pluton, gpml:PoliticalBoundary, gpml:PolygonCentroidPoint, gpml:PseudoFault, gpml:Seamount, gpml:SlabEdge, gpml:StrainMarker, gpml:Suture, gpml:TectonicSection, gpml:TransitionalCrust, gpml:Volcano

gml:validTime

Description:-
The period of time the feature is in existence.
Used by features:-
gpml:TimeVariantFeature

gpml:waterDepth

Description:-
Water Depth in meters at the sample site.
Used by features:-
gpml:OceanDrillSite

Feature Class List

The definition of every possible class of Feature that can be used by GPlates - what the name of the feature is, and what properties it supports. To avoid redundancy in definitions, Features are able to 'inherit' properties from a parent Feature type, and some of the feature definitions are purely abstract features for the purpose of grouping commonly-used properties together.

Don't get too hung up on names of things. Remember that this is a technical document describing to GPlates how the data is structured. If feature type X and feature type Y have the exact same properties, and should be treated the exact same way by the code, then there's no real reason to duplicate their definitions.

gpml:AbsoluteReferenceFrame

Description:-
A means of describing the motion of plates over time, relative to a fixed point or frame.
Comments:-

We derive from TotalReconstructionSequence because that's what an AbsoluteReferenceFrame is - a set of FiniteRotations plus associated gml:TimeInstants. The difference is that an AbsoluteReferenceFrame has a name associated with it (gml:name) and a type, like the "WesselMuller2006 HotSpot reference frame".

There is no feature called 'RelativeReferenceFrame': relative reference frames are implicit.

The description of how this absolute reference frame was created/derived will be in meta data. meta data will be very complex and we'll get into it later.

Properties defined by gpml:AbsoluteReferenceFrame :-
Properties inherited from gpml:TotalReconstructionSequence :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gml:AbstractFeature

Description:-
An identifiable real-world object in a selected domain of discourse.
Properties defined by gml:AbstractFeature :-
Inherited by features:-
gpml:AbstractFeature

gpml:AbstractFeature

Description:-
Highest-level abstract parent of all GPML Features.
Properties defined by gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:Raster, gpml:ReconstructionFeature, gpml:ScalarField3D, gpml:TimeVariantFeature

gpml:AbstractField

Description:-
Abstract superclass for various field data, including stand-alone Contours and outlines.
Comments:-

Assorted contour-like data and (in future releases) gridded data share AbstractField as a parent class.

Types of contour (and later, gridded) data include: Bathymetry, Topography, Gravimetry, Magnetics, GlobalElevation, OceanicAge, CrustalThickness, DynamicTopography, MantleDensity, HeatFlow, SedimentThickness, Roughness, SpreadingRate, SpreadingAsymmetry, Stress.

This is because all contoured data is picked from a gridded source, and similarly with most stand-alone outline data. In addition, there are many, many types of gridded data that we may wish to use in the future. With most of these types, it still makes sense to be able to pick outlines and contours from the grid - they are useful in many cases.

Properties defined by gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:Bathymetry, gpml:CrustalThickness, gpml:DynamicTopography, gpml:GlobalElevation, gpml:Gravimetry, gpml:HeatFlow, gpml:Magnetics, gpml:MantleDensity, gpml:OceanicAge, gpml:Roughness, gpml:SedimentThickness, gpml:SpreadingAsymmetry, gpml:SpreadingRate, gpml:Stress, gpml:Topography

gpml:AbstractGeologicalContact

Description:-
Abstract base for all Geological Contacts.
Comments:-

An AbstractGeologicalContact is simply the surface along which two different rock types are juxtaposed.

Properties defined by gpml:AbstractGeologicalContact :-
Properties inherited from gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:Fault, gpml:TerraneBoundary, gpml:Unconformity, gpml:UnknownContact

gpml:AbstractGeologicalPlane

Description:-
Abstract base for all Geological Surface Planes, including Surfaces such as Bedding Surfaces, Cleavage, intangible planes such as Fold Plane, as well as Contacts and Faults.
Comments:-

An AbstractGeologicalPlane by itself will not be instantiated; You want a subcategory of GeologicalPlane(BeddingPlane, CleavagePlane), or perhaps a FoldPlane, or one of the various specialisations of GeologicalContact.

Properties defined by gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:AbstractGeologicalContact, gpml:FoldPlane, gpml:GeologicalPlane

gpml:AbstractRockUnit

Description:-
Abstract base for all geological rock units.
Comments:-

Use BasicRockUnit for free-form text descriptions or simple extents of the geological rock units on each side of a GeologicalContact (such as Fault, Unconformity).

Specifying an abstract base allows for possible extension later on, e.g. GeoSciML interoperability.

Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:BasicRockUnit

gpml:ArtificialFeature

Description:-
Abstract base for geometry that has been arbitrarily created, or possibly derived from a TangibleFeature.
Comments:-

In contrast to TangibleFeature, this deals with geometry that has been arbitrarily created, or possibly derived from a TangibleFeature. For example, InferredPaleoBoundary is a plate boundary that is assumed to have existed, even though it has long since been subducted under the surface. OldPlatesGridMark is a sequence of lines defined in PLATES data files for annotation.

Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:ClosedContinentalBoundary, gpml:ClosedPlateBoundary, gpml:InferredPaleoBoundary, gpml:OldPlatesGridMark, gpml:PoliticalBoundary

gpml:AseismicRidge

Description:-
Miscellaneous inactive ridge feature.
Comments:-

The term "Aseismic Ridge" is a very general term used by geoscientists that can apply to almost any nonspecific ridge, with the only defining quality being the inactivity of the feature.

For example, sections of a HotSpotTrail might be a chain of Seamounts which are contiguous enough to form a ridge. As well as being Seamounts, the structure can also be termed an "Asesimic Ridge". However, the term can also be easily applied to an Extinct Ridge, or now-inactive remnant spreading ridge (see MidOceanRidge).

As far as the GPGIM is concerned, this might make AseismicRidge into an abstract parent of some sort- however, that would imply that all features inheriting from AseismicRidge would be inactive, throughout their entire lifespan. This is unacceptable, especially considering planned improvements to MidOceanRidge to allow for partial segments of a MOR to become inactive, and also considering that a HotSpot's trail is formed of Volcanoes as well as Seamounts that may be active for some time and later become inactive.

However, there still exist some situations where the term "AseismicRidge" may be the only term applicable, where a ridge is not known to be any other specific type of ridge. AseismicRidge exists in the GPGIM for this purpose.

Properties defined by gpml:AseismicRidge :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:BasicRockUnit

Description:-
Basic definition of a geological rock unit.
Comments:-

This is the simplest way to define a basic rock unit type while allowing for future extension.

BasicRockUnit allows you to describe one side of a GeologicalContact using the standard free-form text properties, plus a polygon extent.

gml:name and gml:description can be used for this specific rock unit.

gpml:subcategory can be used to specify which general categories this BasicRockUnit belongs to, for example, a "Basalt" BasicRockUnit, or "Ophiolite" can be used to define an ophiolite belt, and so on.

Properties defined by gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:FossilCollection_small, gpml:FossilCollection_medium, gpml:FossilCollection_large, gpml:RockUnit_carbonate, gpml:RockUnit_siliciclastic, gpml:RockUnit_evaporite, gpml:RockUnit_organic, gpml:RockUnit_chemical, gpml:RockUnit_plutonic, gpml:RockUnit_volcanic, gpml:RockUnit_metamorphic, gpml:RockUnit_indeterminate_igneous

gpml:Basin

Description:-
Regional scale depression of erosional or structural origin.
Comments:-

Basins can be categorised into many types, and some of these types overlap or are subjective. Rather than attempting to define a fixed subset of these types, it is recommended to use the .subcategory property defined in AbstractFeature.

Suggested subcategories are "Extensional", "Convergent", "IntraCratonic", "Compressional", "Sag", "Thermal", "Erosional", "Unknown".

Properties defined by gpml:Basin :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Bathymetry

Description:-
Sea floor depth data, including bathymetric contours and grids.
Comments:-

Usually measured in m (depth).

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ClosedContinentalBoundary

Description:-
Rigid closed polygon continental crust boundary that can be reconstructed to any time.
Comments:-

Similar (but not identical) to ClosedPlateBoundary, but for crust type differences (oceanic-continental). It can be rotated via the usual reconstruction mechanisms, and the geometry of this boundary is represented in present-day-coordinates.

Properties defined by gpml:ClosedContinentalBoundary :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ClosedPlateBoundary

Description:-
Rigid closed polygon plate boundary that can be reconstructed to any time.
Comments:-

A simple geometric view of a PlateSlab's closed boundary, possibly derived from a TopologicalClosedPlateBoundary. It is reconstructable, and so the polygon is encoded using present-day coordinates. This type of plate boundary might be most useful as a "Grid Mask" for gridded data relating to the plate.

Some standard properties are very useful for a ClosedPlateBoundary. The .reconstructionPlateId property inherited from ReconstructableFeature will allow us to associate one (or more, potentially) gpml:plateId s with the plate boundary, gml:name can be used to name the plate, and validTime indicates the lifetime of this plate polygon.

Properties defined by gpml:ClosedPlateBoundary :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Coastline

Description:-
Present day coastline.
Comments:-

Present day coastline, but can still be reconstructed with the rest of them as a visual aid.

Properties defined by gpml:Coastline :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ContinentalCrust

Description:-
Continental Crust
Properties defined by gpml:ContinentalCrust :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:OceanicCrust

Description:-
Oceanic Crust
Properties defined by gpml:OceanicCrust :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ContinentalFragment

Description:-
A fragment of continental crust that has become detached.
Properties defined by gpml:ContinentalFragment :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ContinentalRift

Description:-
A spreading rift on continental crust.
Comments:-

Functionally, this behaves similarly to MidOceanRidge, but a ContinentalRift is defined for continental crust only.

Properties inherited from gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Craton

Description:-
Large portion of a continental plate that has been relatively undisturbed since the Precambrian era and includes both shield and platform layers.
Comments:-

See Dictionary of Earth Science p132. Includes Shield regions.

Properties defined by gpml:Craton :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:CrustalThickness

Description:-
Crustal thickness data, typically represented using grids, related to Isopach data.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:DisplacementPoint

Description:-
A position used to build deforming regions.
Properties defined by gpml:DisplacementPoint :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:DynamicTopography

Description:-
Elevation differences caused by the flow within the Earth's mantle.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Seismic Tomography (MantleDensity) is used as a source of data to create DynamicTopography.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ExtendedContinentalCrust

Description:-
Continental crust which has been pulled apart.
Comments:-

For instance, near a Continental-Oceanic boundary, there will be a region of TransitionalCrust which is not clearly defined as either oceanic or continental, but there will also be some continental crust which has been pulled apart by the extension, not enough to define new oceanic crust but enough to break the continental crust.

Properties defined by gpml:ExtendedContinentalCrust :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Fault

Description:-
Fracture in a rock body along which observable relative displacement has occurred between adjacent blocks.
Comments:-

Map-view of Faults. Fault now inherits from AbstractGeologicalContact, so we gain the ability to specify what geological rock units lie on either side of the Fault.

Note in the description that a Fault has "observable relative displacement": A Fault is defined by displacement. This is what distinguishes a Fault from an Unconformity. A Detachment is a subcategory of Fault; generally a Detatchment implies massive displacement involved.

We already inherit a centerLineOf via AbstractGeologicalContact and AbstractGeologicalPlane. This line is the 'Strike' of the Fault. This should ideally be a directed line where the order of points matters because we need to define what lies on either side.

We also inherit the description of the 'Dip' of this Fault via AbstractGeologicalContact and AbstractGeologicalPlane. There are two properties, .dipSide and .dipAngle.

There are many different ways to classify a Fault, and they are highly subjective, so remember that we have the 'subcategory' property available.

Suggested subcategories are (1) "Thrust" : A Thrust fault is a term often given to a special case of reverse or compression fault where the hanging wall has thrusted completely over the foot wall. Additional information about e.g. Folding (which might warrant additional subcategories), or perhaps describing specific patterns of the Thrust e.g. "Snake Head", make this an ideal candidate for the .subcategory property, (2) "Detachment" : Often used to describe massive movements of rock created from e.g. detachment of rock from a subducting plate which has moved onto the overriding plate.

Here's what Dictionary of Earth Sciences p201 has to say: Approximately plane surface of fracture in a rock body, caused by brittle failure, and along which observable relative displacement has occurred between adjacent blocks. Most faults may be broadly classified according to the direction of slip of adjacent blocks into dip-slip, strike-slip, and oblique-slip varieties. The term 'dip-slip fault' comprises both normal and reverse slip faults, and the special cases of low-angle lag and thrust faults. Strike-slip faults {wrench, transform, transcurrent} result from horizontal displacement {dextral or sinistral movements} and on a regional scale may involve transpression and transtension.

Properties defined by gpml:Fault :-
Properties inherited from gpml:AbstractGeologicalContact :-
Properties inherited from gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Flowline

Description:-
Tracks plate motion away from spreading ridges over time using half-stage rotations.
Properties defined by gpml:Flowline :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:FoldPlane

Description:-
Inferred plane of geological folding.
Comments:-

Unlike GeologicalPlane(BeddingPlane) and GeologicalPlane(CleavagePlane), which are direct field observations, a FoldPlane is inferred based on many different observations. However, it still shares the same basic properties of a surface indicator, a strike, dip side, and dip angle.

Properties defined by gpml:FoldPlane :-
Properties inherited from gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:FossilCollection_small

Description:-
A collection of small fossils.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:FossilCollection_medium

Description:-
A collection of medium fossils.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:FossilCollection_large

Description:-
A collection of large fossils.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:FractureZone

Description:-
Inactive fracture in the crust that was once part of a Transform boundary.
Comments:-

In PLATES, small fracture-zone lines are used in a segmented fashion- each segment of the line has an appropriate time of appearance and time of disappearance, to simulate the growth of the fracture zone.

For GPlates and GPML, a more ideal solution would treat the entire FractureZone as one complete gml:Feature, with its geometry being time-dependent (possibly using locus geometry). For the present, it is better to follow the older PLATES method, since that is how much of the data is structured and it would require a human to reconstitute the segments.

gpml:FractureZone has an advantage over the old PLATES format; all gpml:ReconstructableFeatures have an optional property called .truncatedSection, which allows for one or more FractureZone pieces to be semantically linked.

Interestingly, a FractureZone's geometry is a SmallCircleArc, roughly indicating the rotation pole when the Transform that created it was active.

Properties inherited from gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:FractureZoneIdentification

Description:-
Pick to identify fracture zone.
Comments:-

The 'pick' can be taken from a magnetic anomaly reading and a ship track - or it can be taken from some other gridded data source, or chosen without any justification at all.

These picks are useful to create Isochrons and align them.

As a FractureZoneIdentification can be picked from a wide variety of sources, it is recommended to use the standard gpml:subcategory property if you want to indicate where this pick comes from.

Suggested subcategories are: (1) "Bathymetry" : chosen based on a Bathymetry grid, (2) "Topography" : chosen based on a Topography grid, (3) "Gravity" : chosen based on a Gravity grid, (4) "Magnetic" : chosen based on a Magnetic grid.

Properties defined by gpml:FractureZoneIdentification :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:GeologicalLineation

Description:-
Undefined linear region.
Properties defined by gpml:GeologicalLineation :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:GeologicalPlane

Description:-
Surface plane indicator based on rock unit observations, e.g. Bedding and Cleavage planes.
Comments:-

While there are a few common clear-cut types of GeologicalPlane, such as a "BeddingPlane" or "CleavagePlane", field geologists may desire many other subcategories of GeologicalPlane, or subcategories of CleavagePlane etc, and this can get very subjective. Therefore, spplication of the .subcategory property (present in all gpml:Features) is advised.

Suggested subcategories are: (1) "BeddingPlane" : Surface plane indicator based on the stratum from the same rock unit, (2) "CleavagePlane" : Surface plane indicator based on the cleavage within the rock unit.

Properties inherited from gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:GlobalElevation

Description:-
Merged bathymetric and topographic elevation data.
Comments:-

Though it is probably a good idea to keep Bathymetry and Topography seperate due to their differences, there are plenty of instances of merged data sets combining ocean depth with land height fields. This Feature supports those cases.

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Gravimetry

Description:-
Gravity grids, outlines, and contours.
Comments:-

Usually measured in mGal.

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:HeatFlow

Description:-
Oceanic heat-flow data.
Comments:-

Heat flow is typically measured by placing devices on the ocean floor to measure temperature. For example, heat will emanate from a MidOceanRidge.

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:HotSpot

Description:-
Location in the mantle linked with high igneous activity.
Comments:-

In the Rotation hierachy, these features will depend on a Hotspot AbsoluteReferenceFrame.

HotSpots are a little unique as they don't move with the plates, but under them (if they move at all).

Properties defined by gpml:HotSpot :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:HotSpotTrail

Description:-
Used to track the paleo-movement of HotSpots.
Comments:-

HotSpotTrails are used to track the paleo-movement of HotSpots. They are gpml:Features in their own right, because for the case of a HotSpot with multiple HotSpotTrail s (one disjoint trail), they can be rotated independently of each other.

Being reconstructable and also describing an inferred sequence of paleo-positions looks like it will get confusing. But presumably, geoscientists are OK with that.

Properties defined by gpml:HotSpotTrail :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:InferredPaleoBoundary

Description:-
Part of a plate boundary defined by hand for real-world geology that no longer exists.
Comments:-

For example, the InferredPaleoBoundary between India and Asia that has since been subducted under the Himalaya.

Properties defined by gpml:InferredPaleoBoundary :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:IslandArc

Description:-
Type of volcanic arc formed by plate tectonics as an oceanic plate subducts under another and produces magma which rises to form the arc.
Properties defined by gpml:IslandArc :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Isochron

Description:-
Line defining points of equal age for oceanic crust.
Comments:-

For the GPGIM1.5, we just want a simple, rigid Isochron replacement for the PLATES model. It includes Paleo-Ridge and Paleo-Transform sections.

A common property associated with an Isochron is its "age". It defines the point in time that this Isochron is believed to originate at, in Ma. However, we already have a .validTime property inherited from TimeVariantFeature, so to work out the 'age' of the Isochron, one can look at .validTime(a TimePeriod).begin(a TimeInstant).

Properties defined by gpml:Isochron :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:LargeIgneousProvince

Description:-
An extensive region of basalts resulting from flood basalt volcanism.
Properties defined by gpml:LargeIgneousProvince :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:MagneticAnomalyIdentification

Description:-
Magnetic 'pick' from sea floor magnetism ship-track data. See also MagneticAnomalyLineation.
Comments:-

The 'pick' is taken from the magnetic anomaly reading and the ship path.

The identifier used for magnetic picks evolved to be a combination of letters and numbers, of the form (C|M)[number][combination of letters].

For magnetic picks, an indication of precisely where on the anomaly the reading was taken is often appended, in the form (o|y)[floating-point number].

The identifier used for magnetic picks evolved to be a combination of letters and numbers, of the form (C|M)[number][combination of letters].

The first letter indicates Cenozoic or Mesozoic era, followed by a number indicating the chron's position in the sequence. However, the early measurements of isochrons were not very high resolution, and many smaller polarity reversals were missed, only to be discovered later as techniques improved. Rather than renumbering everything as new isochrons were discovered, letters from a-z were added after the number, so M14a refers to the first sub-chron located inside the 14th major chron, and if a polarity reversal were located inside that, it would be named M14aa, and so on.

This would result in names such as C34ado0.5, which translates to a Cenozoic isochron, major region 34, sub region a, sub region d, and in the case of this pick the measurement was taken half-way between the "old" and "young" edges.

Properties defined by gpml:MagneticAnomalyIdentification :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:MagneticAnomalyShipTrack

Description:-
Ship Track data for Magnetic 'pick's.
Comments:-

For now, this allows us to define the map-view path taken by a particular ship for magnetic anomaly data. You can give it a 'ship track Id' if you want, via gml:name. The MagneticAnomalyIdentification s or 'picks' have a reference to this Feature to indicate the particular ship track that the pick originated from.

In the distant future, this Feature could also be used to record or reference the magnetic "wiggle" recorded along the ship track.

Properties defined by gpml:MagneticAnomalyShipTrack :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Magnetics

Description:-
Magnetic field feature for grid data and contours.
Comments:-

Usually measured in mT.

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:MantleDensity

Description:-
Density of the mantle, computed using Seismic Tomography.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

MantleDensity data can be applied to the creation of DynamicTopography grids.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:MeshNode

Description:-
Global positions to calculate plate velocities at.
Properties defined by gpml:MeshNode :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:MidOceanRidge

Description:-
A spreading rift on oceanic crust.
Comments:-

The MidOceanRidge class needs to be pretty flexible. In the PLATES methodology, MOR lines are typically used to represent both the 'spreading' and 'transform' sections of the ridge - and so a lot of older data sets will have rigid MidOceanRidges once they are imported. Ideally, they would use an explicit Transform to join up MidOceanRidge and SubductionZone pieces.

The other area that MidOceanRidge needs to encompass is those ridges that have become an "Extinct Ridge" through a process of ridge propagation. This is handled via the .isActive time-dependent property below.

It is possible that later releases of the GPGIM will support a single MidOceanRidge Feature with heterogenous 'segments'.

Properties defined by gpml:MidOceanRidge :-
Properties inherited from gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:MotionPath

Description:-
Tracks absolute plate motion over time.
Properties defined by gpml:MotionPath :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:NavdatSample

Description:-
Abstract base class representing a sample from the North American Volcanic and Intrusive Rock Database (NAVDAT).
Properties defined by gpml:NavdatSample :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:NavdatSampleMafic, gpml:NavdatSampleIntermediate, gpml:NavdatSampleFelsicLow, gpml:NavdatSampleFelsicHigh

gpml:NavdatSampleMafic

Description:-
A sample from the NAVDAT database with mafic chemical composition.
Properties inherited from gpml:NavdatSample :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:NavdatSampleIntermediate

Description:-
A sample from the NAVDAT database with chemical composition intermediate between mafic and felsic.
Properties inherited from gpml:NavdatSample :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:NavdatSampleFelsicLow

Description:-
A sample from the NAVDAT database with low felsic chemical composition.
Properties inherited from gpml:NavdatSample :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:NavdatSampleFelsicHigh

Description:-
A sample from the NAVDAT database with high felsic chemical composition.
Properties inherited from gpml:NavdatSample :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:OceanDrillSite

Description:-
An feature to hold data related to a single dilling site.
Comments:-

A single Ocean Drilling Site, with single point geometry, and various measured properties at the site.

Properties defined by gpml:OceanDrillSite :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:OceanicAge

Description:-
Age of seafloor, for contours and grids.
Comments:-

While oceanic age is most frequently represented with grids, it is still useful to pick out contours of specific ages.

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:OldPlatesGridMark

Description:-
Backwards-compatibility with PLATES "GR" code.
Properties defined by gpml:OldPlatesGridMark :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Ophiolite

Description:-
Uplifted oceanic crust attached to edges of continental plates.
Properties defined by gpml:Ophiolite :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:OrogenicBelt

Description:-
A linear or arcuate zone on a regional scale which has undergone compressional tectonics.
Comments:-

The standard model of an orogenic belt is a linear tectonic region in a mountainous region where two plates have collided. Similar to a subduction zone, one plate has often overridden the other, so we use a similar model to that of gpml:SubductionZone. As with MidOceanRidge, the leftPlate and rightPlate properties are set to advise approximately which plate is overriding which.

While certainly OrogenicBelt can be treated similarly to SubductionZone, as there was presumably a SubductionZone that pulled the OrogenicBelt into existence (eg India and Asia), there exists potential for there to be no clearly defined overriding and overridden plate. Similar to SubductionZone, we have a .subductingSlab property which is optional.

Properties defined by gpml:OrogenicBelt :-
Properties inherited from gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:PassiveContinentalBoundary

Description:-
Border line between oceanic and continental crust.
Comments:-

A quite simple, linelike boundary indicating the change between continental and oceanic crust. Since this change is broad and hard to pin down, we expect two main types of continental boundary, an "Inner" ContinentalBoundary and "Outer" ContinentalBoundary. Naturally, which of these labels gets used to describe a gpml:PassiveContinentalBoundary depends largely on the source of the data, who digitized the line, and whether that aspect of the data was recorded in the original source.

Does not have to be closed, can be a simple line segment. For closed polygons, you want InstantaneousClosedContinentalBoundary and ClosedContinentalBoundary.

Properties defined by gpml:PassiveContinentalBoundary :-
Properties inherited from gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Pluton

Description:-
A body of intrusive igneous rock.
Properties defined by gpml:Pluton :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:PoliticalBoundary

Description:-
A political boundary.
Properties defined by gpml:PoliticalBoundary :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:PolygonCentroidPoint

Description:-
The centroid of a polygon used when meshing a deforming region that contains non-deforming interior blocks.
Properties defined by gpml:PolygonCentroidPoint :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:PseudoFault

Description:-
Fault-like contact caused by ridge propagation.
Comments:-

Due to ridge jump / propagation, and various plate-tec forces in the region, a midoceanridge-transformfault-midoceanridge area may start ignoring the extra midoceanridge and transform, and instead start 'propagating' one ridge to take over the job of the other.

The PsuedoFault is the result of the MidOceanRidge that is 'propagating' into the area previously handled by the Extinct Ridge. The contrast between the newly generated young crust and the old crust made by the Extinct Ridge causes a fault-like appearance- although it is not a true Fault.

Properties defined by gpml:PseudoFault :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Raster

Description:-
Generic multi-band, geo-referenced gridded image data.
Properties defined by gpml:Raster :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ReconstructableFeature

Description:-
Parent of all GPML Features we may want to associate with a plateId and are reconstructable.
Comments:-

A ReconstructableFeature may be rotated relative to another ReconstructableFeature by the action of Finite Rotations (Inside a TotalReconstructionSequence).

Properties defined by gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:ArtificialFeature, gpml:DisplacementPoint, gpml:MeshNode, gpml:MotionPath, gpml:PolygonCentroidPoint, gpml:SmallCircle, gpml:TangibleFeature

gpml:ReconstructionFeature

Description:-
Top-level abstract class that all rotations inherit from.
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:TotalReconstructionSequence

gpml:RockUnit_carbonate

Description:-
A carbonate rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_siliciclastic

Description:-
A siliciclastic rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_evaporite

Description:-
An evaporite rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_organic

Description:-
An organic rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_chemical

Description:-
A chemical rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_plutonic

Description:-
A plutonic rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_volcanic

Description:-
A volcanic rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_metamorphic

Description:-
A metamorphic rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:RockUnit_indeterminate_igneous

Description:-
An indeterminate_igneous rock unit.
Properties inherited from gpml:BasicRockUnit :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Roughness

Description:-
Roughness data computed from Gravity grids.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

This feature is an example of one which would use gridded data almost exclusively, with little need for Contours and outlines. However, in any case of gridded data, there is the possibility that such contours may be desirable, and should be available as an option.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:ScalarField3D

Description:-
Generic 3D field of scalar values representing arbitrary sub-surface data.
Properties defined by gpml:ScalarField3D :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Seamount

Description:-
Igneous cone-shaped mountain that is below sea level.
Comments:-

Includes all variations of Seamounts, such as Guyots; set the .subcategory property (defined in AbstractFeature) to "Guyot" if you're interested in the distinction.

Suggested subcategories are: "Guyot" : A special sub-category of Seamount with a flat top.

Properties defined by gpml:Seamount :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:SedimentThickness

Description:-
Isopach data indicating sediment thickness using grids and/or contours.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

For example, http://www.usawaterquality.org/conferences/2005/Posters/Negrini.pdf

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:SlabEdge

Description:-
A slab edge.
Properties defined by gpml:SlabEdge :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:SmallCircle

Description:-
A global position and small circle radius for small circle visualisations.
Properties defined by gpml:SmallCircle :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:SpreadingAsymmetry

Description:-
Asymmetry in sea-floor spreading rate.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:SpreadingRate

Description:-
Sea-floor spreading rate.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:StrainMarker

Description:-
Location on the surface to show stain data computed from interpolation via a Topologicl Network feature.
Comments:-

StrainMarker features are usually shown with a cross symobol, where the magnitude of each axis shows the value for a principle strain.

Properties defined by gpml:StrainMarker :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Stress

Description:-
Stress grids and contour data.
Comments:-

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:SubductionZone

Description:-
A zone of descending lithospheric plate.
Comments:-

The standard model of a subduction zone is a linear tectonic region which consumes plate material on one side, while being largely 'attached' to a plate on the other side. Similarly to MidOceanRidge, the leftPlate and rightPlate properties are often set to advise approximately which plate is being consumed. The SubductionZone is always 'attached' to the overriding plate, as far as the gpml:plateIds are concerned.

Not necessarily a 'Zone', could be a linelike feature or have an additional polygon geometry. The gml property .centerLineOf is used to indicate where the subducting plate meets the overriding plate.

Properties defined by gpml:SubductionZone :-
Properties inherited from gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Suture

Description:-
Large scale structural feature associated with continental collision, separating crust that once belonged to two different plates.
Properties defined by gpml:Suture :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:TangibleFeature

Description:-
Abstract base for real geological features (compare with 'ArtificalFeature').
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:AbstractField, gpml:AbstractGeologicalPlane, gpml:AbstractRockUnit, gpml:AseismicRidge, gpml:Basin, gpml:Coastline, gpml:ContinentalCrust, gpml:OceanicCrust, gpml:ContinentalFragment, gpml:Craton, gpml:ExtendedContinentalCrust, gpml:FractureZoneIdentification, gpml:GeologicalLineation, gpml:HotSpot, gpml:HotSpotTrail, gpml:IslandArc, gpml:Isochron, gpml:LargeIgneousProvince, gpml:MagneticAnomalyIdentification, gpml:MagneticAnomalyShipTrack, gpml:NavdatSample, gpml:OceanDrillSite, gpml:Ophiolite, gpml:Pluton, gpml:PseudoFault, gpml:Seamount, gpml:SlabEdge, gpml:StrainMarker, gpml:Suture, gpml:TectonicSection, gpml:TransitionalCrust, gpml:VirtualGeomagneticPole, gpml:Volcano, gpml:FeatureCollectionMetadata

gpml:TectonicSection

Description:-
Superclass to group ridgelike and related tectonic features together.
Comments:-

Plate-tectonic features that can form boundaries between plates fall under this class.

Properties defined by gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:ContinentalRift, gpml:FractureZone, gpml:MidOceanRidge, gpml:OrogenicBelt, gpml:PassiveContinentalBoundary, gpml:SubductionZone, gpml:Transform

gpml:TerraneBoundary

Description:-
Regional scale miscellaneous contact line between two rock units.
Comments:-

A Terrane Boundary is a regional scale miscellaneous contact between two rock units.

The rock units do not have to be clearly identified - it could simply be the boundary between a known rock unit and an unknown region, or merely the contact itself.

A Terrane Boundary is a regional scale miscellaneous contact between two rock units.

The rock units do not have to be clearly identified - it could simply be the boundary between a known rock unit and an unknown region, or merely the contact itself.

Properties inherited from gpml:AbstractGeologicalContact :-
Properties inherited from gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:TimeVariantFeature

Description:-
Abstract base class for all features that have a valid time period (compared to instantaneous features).
Comments:-

TimeVariantFeature is one of the parents to the majority of commonly used gpml:Features.

Most, but not all, features will ultimately inherit from our gpml:TimeVariantFeature in order to have the .validTime property. In contrast, features deriving from InstantaneousFeature require a TimeInstant rather than a TimePeriod, and they obtain this via the .reconstructedTime property.

Properties defined by gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:Flowline, gpml:ReconstructableFeature, gpml:TopologicalFeature

gpml:Topography

Description:-
Elevation data, including topographic contours and grids.
Comments:-

Usually measured in m (height).

Currently, this feature provides for contour and outline data. This feature is intended to support gridded data in a future release.

Properties inherited from gpml:AbstractField :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:TopologicalClosedPlateBoundary

Description:-
A plate boundary formed by rubber-banding vertex lists, which are obtained by intersecting the geometry of other features.
Properties defined by gpml:TopologicalClosedPlateBoundary :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:TopologicalSlabBoundary

gpml:TopologicalFeature

Description:-
Abstract base class for features that topologically reference geometries from other features.
Comments:-

In comparison with ReconstructableFeature and InstantaneousFeature: (1) does not have geometry of its own, (2) should be able to exist for more than an instant, so it is not really an "instantaneous" feature.

JB: A topological plate boundary doesn't need any of the reconstruction timeline stuff, since the whole key to its existence is that it borrows its geometry from other features, which will be reconstructable, and thus will have their own reconstruction timelines.

Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:TopologicalClosedPlateBoundary, gpml:TopologicalNetwork

gpml:TopologicalNetwork

Description:-
A triangulated region inside a topological boundary, comprising internal constraint geometries and excluding interior polygons, used to calculate velocities in deforming regions.
Properties defined by gpml:TopologicalNetwork :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:TopologicalSlabBoundary

Description:-
A topological closed boundary around a subducting slab.
Properties defined by gpml:TopologicalSlabBoundary :-
Properties inherited from gpml:TopologicalClosedPlateBoundary :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:TotalReconstructionSequence

Description:-
A sequence of total reconstruction poles for a specific fixed/moving plate pair.
Comments:-

This feature represents a sequence of total reconstruction poles for the same (fixed plate Id, moving plate Id) pair which are temporally adjacent -- and thus, which may be interpolated.

Quoting JB: "How can a snapshot be captured of a feature which is an ephemoral result of an interpolation? Should this snapshot instead refer to the two features between which the interpolation occurred? What if a new feature is added "between" these two features, meaning that the two features are no longer temporally adjacent and hence no longer valid for interpolation? Does this then imply we need to capture a snapshot of the *whole feature collection*, which itself will change whenever any another unrelated feature is added or removed?"

Properties defined by gpml:TotalReconstructionSequence :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-
Inherited by features:-
gpml:AbsoluteReferenceFrame

gpml:Transform

Description:-
Regional scale strike-slip plate boundary.
Comments:-

Used to link MidOceanRidge s and SubductionZone s together to form a closed plate boundary.

This may not see as much use as MidOceanRidge; the current methodology employed in PLATES data files typically ignores Transforms altogether, and uses 'MOR' lines for both the spreading ridge and the transform 'kink's. In addition, the parts of simple PLATES-style Isochron lines that are perpendicular to the ridge can also be considered 'transforms' or 'fracture zones', because they indicate the paleo-offset between two ridge sections.

Properties defined by gpml:Transform :-
Properties inherited from gpml:TectonicSection :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:TransitionalCrust

Description:-
Undefined region between continental crust and oceanic crust.
Comments:-

As the transition between continental crust and oceanic crust is such a large-scale transition, there will always be a "grey area" where crust cannot be clearly identified as either oceanic or continental.

Properties defined by gpml:TransitionalCrust :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Unconformity

Description:-
Surface of contact between two differing rock units.
Comments:-

An Unconformity is a type of AbstractGeologicalContact. As such, it inherits GeologicalContact's properties '.leftUnit' and '.rightUnit', which allow you to specify what AbstractRockUnits are separated by this Unconformity.

An Unconformity is not the same as a Fault. In addition, Unconformities typically have their most interesting detail in cross-section views, such as different layers of sediment - it is never a regional scale contact.

Any gml:LineStrings associated with this Unconformity will have to be restricted to a map-view for the time being.

Properties inherited from gpml:AbstractGeologicalContact :-
Properties inherited from gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:UnknownContact

Description:-
Regional scale unknown geological contact line.
Comments:-

Unlike Unconformity and Fault, which deal with fine-grained map views, UnknownContact is for regional scale map views which don't necessarily correspond to physical Faults and Unconformities. It can be used where the reason for the contact is unknown or not specified.

Properties inherited from gpml:AbstractGeologicalContact :-
Properties inherited from gpml:AbstractGeologicalPlane :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:VirtualGeomagneticPole

Description:-
Magnetic pole location consistent with the observed direction of remanence at a particular location.
Properties defined by gpml:VirtualGeomagneticPole :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:Volcano

Description:-
An opening in the crust, which allows magma to escape from below.
Comments:-

Single Active Volcano with point geometry. Might be referenced from other igneous Features, e.g. HotSpotTrail or IslandArc.

Properties defined by gpml:Volcano :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-

gpml:FeatureCollectionMetadata

Description:-
Contains metadata which applies to the whole feature collection.
Comments:-

metadata for feature collection

Properties defined by gpml:FeatureCollectionMetadata :-
Properties inherited from gpml:ReconstructableFeature :-
Properties inherited from gpml:TimeVariantFeature :-
Properties inherited from gpml:AbstractFeature :-
Properties inherited from gml:AbstractFeature :-