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I have a DEM that am reclassifying into two classes. One areas less than or equal to 1000 and the other areas greater than 1000. Am accomplishing this using the reclassify Tool in ArcMap 10.1.

The results are a range that I don't understand,what could be the problem Results

The reclassify tool Reclassify window

Properties of DEM

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    How exactly are you reclassifying the DEM based on areas? When you are reclassifying are you sure you have it selected to only 2 classes? Looks like you have it on 9 classes Feb 10, 2016 at 12:10
  • Post a screen shot of your reclassify tool and the properties of the DEM so we can have a look.
    – Nxaunxau
    Feb 10, 2016 at 12:22
  • Seems that you're using the method for reclassification correctly. However, I wonder why your raster has a count of -2086568736... Also, have you tried to get rid of the negative values in a first step?
    – dru87
    Feb 10, 2016 at 12:34
  • The negative values are okay, its an area bordering an ocean Feb 10, 2016 at 12:37
  • what coordinate system is your data in? The cell size seems to indicate that it is in a geographic coordinate system rather than a projected coordinate system. Am i correct in assuming you are trying to find areas below and above 1000m?
    – Nxaunxau
    Feb 10, 2016 at 12:38

1 Answer 1

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Try splitting your raster into smaller parts. It seems to be really big.

I just found this post: http://forums.esri.com/Thread.asp?c=93&f=995&t=225045, someone had a similar problem as you:

Quote from link above: Any count exceeding 2^31-1 will therefore "roll over" into the most negative numbers; for instance, (2^31-1) + 1 will appear as -2^31. For some analyses this may make no difference provided the original count is less than 2^32, but for many analyses you will get incorrect results.

As your count of raster cells is negative, I suspect the size of the raster (and therefore the number of pixels) to cause the problem.

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