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I am trying to reclassify many euclidean distance layers (which are based on lines) each into 10 classes of equal area. When I attempt to do this, using the quantile reclassification method, some classes contain twice as many cells as others. I thought that using the quantile method, the cell counts of each class were supposed to be roughly equal. The "Slice" tool does generate classes of equal cell counts when using the "equal area" method, but I need to know the break values, which the slice tool does not give (But reclassify does). How can I reclassify these layers into ten classes of equal area and know the break values of each class?


I have found that this can be done by first converting the floating point raster to an integer using the floating point tool.

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there is a warning about using the Quantile breaks noted in the help file.

"Because features are grouped in equal numbers in each class using Quantile classification, the resulting map can often be misleading. Similar features can be placed in adjacent classes, or features with widely different values can be put in the same class. You can minimize this distortion by increasing the number of classes"

See the graphic examples in that thread for more information.

  • Thanks Dan, This is actually a different problem than the one I am talking about. I don't care about so much about the variance of the features within classes, but more about the cell counts of each class being more or less equal. Increasing the number of classes actually makes this problem worse. However, as I mentioned in my edit to my original post (only after you replied), I have found a way around this by converting the raster to an integer before carrying out the reclassification, though it is still confusing as to why this step was not necessary when using the "Slice" tool. Thanks – jc22 Aug 2 '14 at 6:08
  • Did you scale up by a factor of 10 prior to taking the int of the data otherwise you may be affecting the data itself, particularly if the values are small and/or their range is small. – user681 Aug 2 '14 at 8:07
  • No, I only need a resolution of 20m, and the units of the euclidean distance raster are meters, so whilst i did lose some resolution, this was negligible. Thanks for the heads up – jc22 Aug 2 '14 at 10:48

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