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GPlates Model Importer
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GPlates Model Importer

The GPlates Model Importer is a tool for importing GPlates models into PaleoGIS format.  GPlates models include a rotation table file and a polygon shapefile.  The shapefile is the equivalent of the “cookie-cutter” layer in PaleoGIS plate models.  Both the rotation table and the shapefile are needed to be able to import a GPlates model into PaleoGIS format.  This tool is only available for use in PaleoGIS v5.0.

Installing the Tool

If the GPlates Model Importer is not already installed in the PaleoGIS: Analysis Tools toolbar in your version of PaleoGIS, install it as follows:

  1. Put the GPlates Model Importer file (GplatesModelImporterExt.dll) in the PaleoGIS installation directory at C:\Program Files (x86)\Rothwell\PaleoGIS.  You will need administrator permissions on your computer to do this.

  1. In PaleoGIS, open the Configuration window and go to the Application settings tab:

  1. Scroll down to the bottom of the table.

  1. In the empty bottom row of the table, enter “PG_ANALYSIS_x” into the Name column, where x is the next higher number after the highest existing PG_ANALYSIS entry.  For example, if the highest existing PG_ANALYSIS entry is PG_ANALYSIS_7, enter “PG_ANALYSIS_8” in the Name column in the empty row.

  1. Enter this text into the Val column (copy and paste to avoid typos):

GPlates Model Importer|GplatesModelImporterExt.dll#GplatesModelImporterExt.GplatesModelImporterExt

  1. Click the Save Updates button.

  1. Close and then restart ArcMap.

  1. The importer tool should now appear in the drop-down menu in the PaleoGIS: Analysis Tools toolbar:

Using the Model Importer

  1. In the PaleoGIS: Analysis Tools toolbar, select the GPlates Model Importer from the drop-down menu and click Go to open the tool window:

  1. Fill in the form according to the descriptions below.

Rotation Table: The GPlates rotation table file (extension = .rot) for the model being imported.  Use the button to the right of the text box to browse to and select the rotation table.   Note:  Currently only a single rotation table can be imported using this tool.  If the model has multiple rotation tables, you must first concatenate them into a single rotation table before importing the model.

Cookie Cutter

Shapefile:  The polygon shapefile used as the model “cookie cutter” layer.  Use the button to the right of the text box to browse to and select the shapefile.  In GPlates this shapefile is usually called the static polygon shapefile or something similar.

The following three drop-down menus will be populated after the cookie cutter shapefile is selected.  Each menu contains a list of all the shapefile attribute fields.  

Plate Code Field:  Select the field name that corresponds to the plate code field in the shapefile.  This field is usually called PLATEID1.

Appearance Field:   Select the field name that corresponds to the plate appearance field in the shapefile.  This field is usually called FROMAGE (i.e., From Age, not French cheese).

Disappearance Field:   Select the field name that corresponds to the plate disappearance field in the shapefile.  This field will commonly be named TOAGE (i.e., To Age).

Model Settings

Timescale:  This drop-down menu contains a list of timescales that are available in PaleoGIS.  The selected timescale will determine the geologic ages and their associated numeric age ranges that will be shown in the PaleoGIS reconstruction age drop-down menu when the model is loaded in PaleoGIS.  If you would like to use a timescale that is not listed, you will need to manually add it to the model later.

Minimum Reconstruction Age (Ma):  The youngest age in millions of years ago (Ma) for which the model is valid.  A negative number is generally used for this value, indicating an age in the future, even if the youngest valid age for the model is 0 (present day).  This text box is automatically pre-populated with -1, which should be acceptable in most cases.

Maximum Reconstruction Age (Ma):   The oldest age in millions of years ago (Ma) for which the model is valid.  This value should be available in the GPlates model documentation. Example: If the model is valid from 0 Ma to 250 Ma, then enter 250 in this text box.

Citation:   The model citation text that will appear in the map label in PaleoGIS reconstructions:

Model Geodatabase Name: The name that will be given to the new PaleoGIS model geodatabase.  

Output Directory:  The directory where the imported model will be output to.  Use the button to the right of the text box to browse to and select the desired output location.

 

  1. Click the Import Model button to start the import process.  

  1. When the import process is complete, you will be shown a “Done!” message and a box showing reference plate crossover issues will open at the bottom of the GPlate Model Importer window:

Use your mouse or Ctrl-A to select all of the text in the box and copy and paste it into a text document for later reference.  See the Fixing Crossovers section of this document for more information about how to use this information.

  1. Close the GPlates Model Importer window.

  1. You can now register and load the imported model in PaleoGIS, after which you should make any necessary crossover corrections as described below.

Fixing Crossovers

Reference plate crossovers in plate model rotation tables are handled somewhat differently in PaleoGIS than in GPlates.  When a plate has sequential crossovers (i.e., when two or more consecutive ages for a specific plate have crossovers) minor changes must be made to the rotation table for correct operation.  Also, sometimes there are invalid crossovers which have only one pole instead of two at the crossover age.  Both types of issues should be fixed before performing reconstructions with the model or you may get erroneous results.  Information about crossovers in PaleoGIS can be found here.

You should use the PaleoGIS Model Validator tool in the PaleoGIS: Analysis Tools toolbar on the newly imported model to locate and delete unused poles of rotation in the model before making changes to the rotation table.  This way you won’t waste time fixing crossovers that aren’t used.

Once you’ve registered and loaded the model in PaleoGIS, you can easily access and edit the model’s rotation table as follows:

  1. Click the Pole Set Maintenance button in the PaleoGIS: Plate Model Tools toolbar:

  1. In the Edit Poles section at the bottom of the window that opens, select “T_Model_Rotations” from the drop-down menu and then click the Edit button:  

  1. The model’s rotation table will open in a window where you can edit the poles of rotation to make any needed crossover changes: