A GST file is a GIS map file format that contains geographic data and visual map of a mapped area. It is used by the MapX (developed by UNEP/GRID-Geneva and UNEP for managing geospatial data on natural resources) and MapXtreme mapping software (a software development toolkit used to build custom GIS applications) that are online platforms for managing geospatial data on natural resources. A GST file contains geographic information in the form numeric as well as raster images that are overlayed on the map.
GST File Format - More Information
GST files are saved in proprietary file format and its internal file format details are not available publicly for developer’s reference.