I have mosaiced 8 SRTM DEM tiles in order to get one raster layer of elevation. When I use "Mosaic to New Raster" tool I set as a pixel type format "16 bit signed" because this is the format that SRTM uses. When I construct slope/aspect/curvature the raster changes pixel type and from 16 bit signed becomes 32 bit float.

Why does this happen and does it corrupt my analysis?

I use ArcGIS Desktop 10.2.

  • Depending on the slope method (degree, percentrise) the numbers could potentially be less than 1 and greater than 0. These values need to be expressed as floating point! Feb 8, 2015 at 21:14

1 Answer 1


Each of the outputs that you described (slope, aspect, and curvature) are terrain attributes that are naturally described as rational numbers. As such, you would expect that the outputs of these tools would be floating point rasters even if the input DEM uses integer level data to characterize elevations. And no, it does not corrupt your analysis. The only effect is that it will double your storage size, but necessarily so.

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