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Adding Missing GTX Files 


Adding Vertical Datum (GTX) Files


Vertical datum grid shift files (GTX) are used for shifting and transforming between vertical datums. Sometimes the Well-Known Text (WKT) of one of the coordinate systems in your project references a particular GTX file that was not bundled with your installation, or the reference itself is missing from the WKT. The steps below describe how to add the missing GTX information in both of these cases.

To add missing GTX information:
  1. Download the required GTX file.
    Note: Other GTX files can be downloaded from here: Additional GTX files can be found on these websites:

  2. Copy the GTX file into the proj subdirectory under the product’s application files directory, e.g., C:\Program Files\Skyline\TerraExplorer Pro\proj\RAF18.gtx
  3. Add the following reference within the WKT's VERT_DATUM object that is under the VERT_CS object. See example at the bottom of this page.