# Calculate in ArcMap?

I need some help with a raster file in ArcMap. The raster is a validation file for a classification that should follow after. Therefore, I need to "cut" the upper and lower 5% of the data in the raster. My histogram looks like this:

I want to solve this in ArcMap because it failed at loading it into RStudio as the program cannot allocate the vector because of its size. My aim is to have a new value range that I can use for a classification.

Does someone know a way to do this?

• Is that 5% of cell area on both ends or 5% of the value range on both ends? When you figure out the precise lower and upper limit you can use ExtractByAttributes resources.arcgis.com/en/help/main/10.2/index.html#//… to extract the in-between values if you have access to the spatial analyst extension. – Michael Stimson Nov 18 '17 at 12:10
• It is about the cell area. In fact the new value range is the result I want to get. Your solution would work the other way round when I still know the new value range. Do you know a solution for the calculation of this values as well? – Thessla Nov 18 '17 at 12:36
• It sounds like you need to compile a list of values and occurrences, sort and select cells (in Excel) until the sum of counts = 1/20 of the total sum of cells revealing the min/max bounds of 'real' data. Not something I'd like to do on a large raster. I know of no simple way to achieve this; how fluent are you in python? – Michael Stimson Nov 18 '17 at 12:56
• Hmm, that is not what I wanted to hear, haha! :) – Thessla Nov 18 '17 at 13:03
• Convert it to integer, using Int(R*100). Table of result will have enough info for your task. – FelixIP Nov 18 '17 at 17:32