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I have a set of raster (floating point) i.e A daily rainfall intensity data for a year, now i need to select and group these raster in to various percentile categories, Above 90th percentile, 50-90, 10-50, below 10. how to achieve this using ArcGIS 10.2 ?

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If you are doing percentiles (10 of) then you can use Slice, otherwise if you need more control (perhaps one range is 20%, or 5%) then Reclassify by Table will serve you better.

If you have lots of data to accumulate (I seem to remember a question like this for Africa very recently) you will need to accumulate using the Raster Calculator to a sum of the rainfall, then if you need to divide by the number of inputs for an average.

  • Can u guide me through it as I'm totally new on this., how to achieve it using raster calculator, some examples. – MSB May 6 '14 at 3:08
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    Here is a link to the documentation resources.arcgis.com/en/help/main/10.1/index.html#//… What you want to do is add a bunch of them in ArcMap and search for raster calculator and then execute it from the search window which brings up a dialog, then you double click each layer in the left window and in between press the plus button. This will add the values into an output raster. If you have python experience it may be easier to build the dialog but that's essentially all there is to it. – Michael Stimson May 6 '14 at 3:40
  • I got it on how to use Raster Calculator many thanks, How to run Percentiles in it for the following "A daily rainfall intensity data for a year, now i need to select and group these raster in to various percentile categories, Above 90th percentile, 50-90, 10-50, below 10" – MSB May 8 '14 at 9:52
  • Here's a good post that shows the syntax, it's in python but the tool is the same gis.stackexchange.com/questions/95027/… using the con tool help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//… you will need three con statements to get your results.. first less than 10, second less than 50 then less than 90. – Michael Stimson May 8 '14 at 21:45

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