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Data Users

Learn how to find, appraise, crop and access data on any Koordinates site.

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  4. ASCII Grid format

ASCII Grid format

Esri ASCII Grid is a widely supported text-style grid format. Because Ascii Grids have no spatial index, it can be difficult for some software applications to handle. In addition, Ascii Grid is an inefficient file format and typically results in extremely large files. For this reason, Koordinates does not recommend using Ascii Grid for raster imports or exports.

Recommended alternative

Koordinates recommends that users instead download in GeoTIFF.

How Koordinates handles Esri ASCII Grid

If you do download using Esri ASCII Grid, note that, to keep the file size reasonable, Koordinates uses the format string "%.6g" to write values for downloading non-integer grids. For some layers this may result in a slight loss of precision.

Specifically this means:

  • Up to 6 significant figures in output.
  • Meaningless zeroes after the decimal point are stripped.
  • Some (very small/large) values will use exponential notation.

Also, for reprojected grids, we include a NODATA value in exports to delineate the area where there was no source data. This may be provided by the platform, though generally we will re-use the NODATA value provided in the source data.