TNTgis - Supplemental Datum Transformations

TNTmips seamlessly handles the display of multiple layers having different coordinate reference systems. Layers are automatically reprojected to properly overlay each other via on-the-fly resampling to the target reference system. The datum transformation specified in the object's georeference determines how coordinates are converted from one datum to another. When setting up the georeference you can accept the default transformation for the Coordinate Reference System or specify one that is more accurate for the area. Furthermore, the transformation can be set whenever a Coordinate Reference System is selected.

All transformations for supported datums are listed in the Datum tab of the Coordinate Reference System window including supplemental transformations. If you select a transformation that is not already installed a message will appear indicating you need to install the supplemental transformation files. Use the link below to download the supplemental grid datum transformations for your operating system.

• Tutorial: Coordinate Reference Systems

The additional .gsb and .ref files will be installed into the DatumTrans folder to be used with TNTgis software. (Specifically — C:\ProgramData\MicroImages\DatumTrans on Windows and ./Library/MicroImages/DatumTrans on Mac.) This folder is independent of version, however, TNTgis 2018 or later is required in order to use these transformations.