In addition to the MapInfo Pro read/write grid handler (*.MIG) we also supply READ-ONLY grid handlers to support the direct opening of the following grid file formats:
- DEM-USGS ASCII(*.DEM)
- DTED-levels 1, 2, and 3 (*.DT0, *.DT1, *.DT2)
- GTOPO30 (*.DEM)
You can open these grid file types directly from the Open dialog box (on the HOME tab, from the Open list, click Table). You will see the file extensions listed next to the Grid Image file type in the Files of type drop-down list in the bottom of the dialog box. Because the handlers are read-only, they cannot be used to create grid files during the thematic mapping process.
If the relief shading option is enabled (in the Create Thematic Map - Step 3 of 3 wizard panel, click Styles and then Grid Appearance), a separate file will be created to store the hill shade information. The hillshade file is stored in the same location as the grid file and has the same base name as the grid but with the extension ".MIH". If the grid file is read-only, for example, it is located on a DVD, the .MIH files will be created in the same location as the .TAB file. The .TAB file will contain a new metadata key, for example:
"\Grid\Hillshade File" = "d:\tmp\AntiochSouth.MIH"