Save DEM/Grid

Option on File menu when map has associated DEM.

  • Entire DEM, MD DEM: save entire DEM in MICRODEM format.
  • Current subset, MD DEM:  save portion of DEM on current map area in MICRODEM format.  Use this if you have a very large DEM, and want to use only a small portion of it. It will take up less memory and disk space, and load faster.
  • Pick corners, MD DEM: select the region to save using the keyboard
  • Portion of DEM with data
  • GeoTIFF:  Missing values will have value defined for Nulls set for DTED export. The file will be saved with the same number of bits as the DEM.  You can force the DEM to have the number of bits you desire with the Pick DEM bits option.
  • ASCII
    • ASCII XYZ
    • USGS ASCII:
    • ASCII Arc Grid: this has no information about the datum or projection.
  • DTED: export to NGA format.
  • BIL produces five files, .HDR, .PRJ, .BLW, .STX, and .BIL.  Format used by USGS Seamless Server.  Only available for geographic DEMs.
  • Grid float: produces three files, .HDR, .PRJ, and .FLT.  Format used by USGS Seamless Server.  Only available for geographic DEMs.
  • DBF: save as dBase table.  You can select a thinning factor to cut down on the size of the file, and max/min values to export. A thinning factor of 2 will give a file about 1/4 the size of the original.  There will be limits on how large a grid this will work with.
  • GeoJSON-G: saved in ASCII GeoJSON, and then BZ2 compressed.
  • Caveat emptor: These are not tested regularly (meaning it has been years since they have been checked), and will not be improved.
    • 3d (OBJ):
    • 16-big BSQ
    • Surfer grid
    • PGM:
    • PNG
  • Reinterpolate DEM: resample entire DEM. 
  • Blank grid new resolution, UTM or lat/long.  This will have the same effect as reinterpolating, and setting the entire grid to missing data.
  • Pick DEM bits: select an appropriate mode, as the grid with be rounded and clipped to the specified range.
    • bytes: 0-255
    • integer 16: -32K to 32K,
    • word: 2 byte, 0 to 64K
    • floating point: 4 byte IEEE float 
  • Create image to match DEM: creates a new map window with the same dimensions and projections as the DEM, and interpolates an image.  This will not have any overlays and will not remember how to redraw itself; if you want that, save this image (File, Save map as image).

Last revision  5/2/2017