Convert rasters from TAS to ArcGIS

TAS (Terrain Analysis System) is a software for geomorphological terrain analysis developed by John Lindsay during his time at Manchester University. John has now moved on to his next project, Whitebox GAT, but we still use TAS for various tasks. This is how to get elevation data from TAS into ArcGIS:

In TAS elevation is modeled as raster, and usually pixels have decimal values (aka floating point data). The best storage format for decimal values with ArcGIS is the ArcGIS GRID format, so you should convert into this format.

The easiest way to convert a TAS floating point raster to the GRID format is by using the Arc Binary format as interchange format:

  1. In TAS go to File > Import/Export > Raster > Export >ArcView Binary Raster Format.
  2. Select the TAS file (e.g. “myfile”)
  3. Specify an output file name (“myfile ArcBinary”)
  4. Click OK. This creates two files, a .flt and a .hdr
  5. In the ArcMap or ArcCatalog toolbox go to Conversion tools > To Raster  > Float to Raster
  6. As Input Raster File select the .flt file created by TAS (“myfile ArcBinary.flt”)
  7. Specify an output raster. The filename must have no blanks and max. 13 characters, so e.g. “myfile_1”
  8. Click OK to run the conversion
  9. The GRID dataset is not aware of its spatial reference system, so assign the correct reference system in ArcCatalog.
  10. View the output in ArcCatalog / ArcMap and verify it is correct.

Note 1: The resulting GRID file is actually a set of files and folders. To manage GRID files (move, rename, etc.) you have to use ArcCatalog.

Note 2: The procedure above is designed for floating point rasters. If you have integer rasters (no decimal places) export from TAS as “ArcView ASCII Raster File Format” an import into Arc with the ASCII to Raster tool.


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