Hi all,
We are happy consumers of National Elevation Dataset DEM data from seamless.usgs.gov. One major problem is that while you have 4 GRID format options on download none of them will come directly in to MapInfo Pro or Vertical Mapper 3. The default format is ArcGRID (proprietary, bad form guys). Then you get BIL, GridFloat, and TIFF.these are either image-only (?) or beyond the GRID understanding of the tools I mentioned. See help excerpt below. This can be conquered if you happen to have some esri tools around (like spatial analyst) for exporting from ArcGRID to ASCII grid. What I'm wondering is if any of you Raster folks have a trick or a utility to reconstitute something like DEM or ASCII grids for import into VM3 from one of the formats? Thanks! ------ ArcGrid is an Arc/Info proprietary format. Some other software packages can read the ArcGrid format. Customers who specify ArcGrid will be delivered a workspace. The workspace is not tarred or gzipped. BIL is a non-proprietary format made by running the GRIDIMAGE command in Arc. The data is a simple binary raster format (signed integer data). There is an accompanying ASCII header file that provides file size information (number of rows and columns). The data are stored in row major order (all the data for row 1, followed by all the data for row 2, etc.). GridFloat is a non-proprietary format made by running the GRIDFLOAT command in Arc. The 32-bit (4 byte) is a simple binary raster format (floating point data). There is an accompanying ASCII header file that provides file size information (number of rows and columns). The data are stored in row major order (all the data for row 1, followed by all the data for row 2, etc.). More information about binary floating point is at: http://grouper.ieee.org/groups/754/ http://www.math.grin.edu/~stone/courses/fundamentals/IEEE-reals.html http://www.psc.edu/general/software/packages/ieee/ieee.html TIFF for NED and SRTM is a 32 bit floating point grid format. More information on the 32 bit floating point TIFF is at: http://partners.adobe.com/asn/developer/graphics/graphics.html Will Mitchell Mitchell Geographics, Inc. 496 Congress St Portland, ME 04101 ph 207.879.7769 fx 207.253.5756 <http://www.mitchellgeo.com> www.mitchellgeo.com
