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I calculated the Slope of the area that I'm working on, and I was wondering if there is a way to calculate the actual percentage of each bracket, meaning the percentage of contribution of each class. The Slope is a floating point type of file and I cant convert it to polygon. Any advice could be helpful.

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  • You need to convert it to an INTEGER raster using the Spatial Analysts tool int(). This will allow you to create an attribute table and then its a simple matter of looking at the count against number of cells with values. – Hornbydd Dec 17 '18 at 23:40
  • I did as you said and it gave me a layer with an attribute table of 260 rows. :-/ – Mohamed Imbaby Dec 18 '18 at 0:04
  • Can you edit your question and show that, I would have expected 90 rows, 0 to 90 degrees. But you have learnt the lesson, to get counts of cells you need your raster to be an integer raster. – Hornbydd Dec 18 '18 at 0:26
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You can use Reclassify tool to reclassify your slope raster into the ranges you want. The Reclassify tool exists in ArcToolbox -> Spatial Analyst Tools -> Reclass -> Reclassify.

When you run the Reclassify tool, you need to rearrange the cell values as the following (the original slope values may look different in your case):

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The output reclassified raster will as follows:

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When you open the attribute table you will have three columns: OID, Value, and Count. Right-click the Count Column and go to Statistics:

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Look at the sum, this is the total number of cells with values:

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Copy the Sum value, then add a new column of type Double, name it Percent,and calculate the percentage of each class using Field Calculator:

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