All of the coordinate systems were directly specified. However, my version of ContextCapture only currently provides two vertical datums by default: EGM96 geoid height and NGF-IGN69 height (French National Vertical Datum). As such, CC has no vertical datum transformation information for NAVD88 exists within the program. On pages 131-132 of the manual it specifies, "Some spatial reference systems use external dependencies which, prior to their use, must be installed in the "data\gdal" subdirectory of ContextCapture installation directory. For instance, a spatial reference system with a custom vertical coordinate system may use a GTX grid to approximate the geoid." Does this mean I should just copy additional .gtx files into that subdirectory? Do I also need to import grid transformation files? If so, what format should I use?
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