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ArcGIS Custom Transformation (.gtf) shift inverted in v10.7

Question asked by Hydronaut on Apr 22, 2020
Latest reply on May 6, 2020 by MKennedy-esristaff

Hello all,

 

In my organisation we have historically created custom transformations (.gtf) that carry 7 parameter shift values between GDA94 (EPSG:4283) and WGS84 (EPSG:4326). We constructed these in ArcMap 10.3 and have recently upgraded to 10.7.

 

We have noticed a few differences between 10.3 and 10.7, such that:

  1. Copying the .gtf files created in 10.3 and inserting them into the Custom Transformation folder in 10.7 results in Error 000365 when attempting to run the 'Project' tool.
  2. The way the .gtf file is created appears to be different between ArcGIS versions. Interestingly, the input and output coordinate systems are listed in opposite order when the 2 .gtf files (10.3 v 10.7) are compared.
  3. When copying and pasting the parameter values from the 10.3 .gtf file to a new custom transformation in 10.7, you would expect to see the shift occur in the same direction as occurs in 10.3. Instead, it seems the data shift is in fact in the inverse direction, which is obviously of concern.

 

Can anyone explain if the way custom transformations are constructed has changed between 10.3 and 10.7, and why we are experiencing inverted shifts between GDA94 and WGS84?

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