TRN is a TatukGIS specific file generated by a layer rectification job (such as using the TatukGIS Editor product) to store information relating to the transformation of a layer performed by the rectification process, including the rotation, scaling, any skewing or warping, and GCP information. The TRN file works together with a PRJ file, which is also generated by a layer rectification job to hold the coordinate system information for the rectified output.
Because a layer rectification job does not make (save) any changes to the layer file (and does not create a new layer file), the TRN file containing the transformation information must be kept (along with the PRJ file) with the layer file in the same folder. Each time the layer is opened in a TatukGIS software product, the information in the TRN and PRJ files is used to on-the-fly transform the layer display to the rectified result. Removing or deleting the TRN file for layer clears the rectification transformation.
A rectified layer can be saved without a TRN file (such as to open a rectification result in a non-TatukGIS software product that does not support TRN files) by exporting the rectified layer display to create a new vector or image layer. Because the export is post-rectification, the newly created layer file inherently reflects the rectification transformation. A TRN file and on-the-fly transformation are no longer required. Use the Editor File/Export to image function to export an image layer and the Layer/Export function to export a vector layer.
The TRN file has the same file name as the layer file (including the extension), followed by the *.TRN extension, e.g., the TRN file for a layer named sample.shp will be sample.shp.trn.