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I have a elevation raster (1 arc second) downloaded from USGS site. Before adding it to ArcMap I changed the display units to meters.The projection system for this raster is GCS_1983. When I use the slope tool under the spatial analyst tool , it is unable to create the slope layer.The data type for the image is floatng.What could be possibly be wrong here.

enter image description here

Even after reprojecting it I get the same error. enter image description here

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  • The cell size is 9.25925925930002e-005
    – SNT
    Commented Apr 28, 2013 at 21:22
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    You need to do more than change the display units. You need to reproject the raster to a projection that uses metres and rerun the slope analysis.
    – Fezter
    Commented Apr 28, 2013 at 23:11
  • The title says "Error" but no error seems to be mentioned in the question.
    – PolyGeo ♦
    Commented Apr 29, 2013 at 8:38

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Despite changing the display units, your raster still is still using a Geographic Coordinate System. Trying to run a slope analysis on such data is invalid. Slope (rise/run) doesn't make sense with degrees as the unit because the distance of 1 degree at the equator is greater than 1 degree near the poles.

You will need to reproject your raster to a coordinate system that uses metres as the units.

Re-run your slope analysis on the new data and you should be fine.

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  • How could I find which UTM zone for the raster to be reprojected.
    – SNT
    Commented Apr 28, 2013 at 23:53
  • Even after reprojection it doesnt help it...
    – SNT
    Commented Apr 29, 2013 at 1:19
  • What error message are you getting?
    – Fezter
    Commented Apr 29, 2013 at 1:22
  • What projection did you use?
    – Fezter
    Commented Apr 29, 2013 at 1:23
  • NAD 1983 UTM Zone 14N.The error is same as above in the original question here. Display units are in meters. Anything else I am missing here.
    – SNT
    Commented Apr 29, 2013 at 1:25

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