I am calculating Geometric Mean for land degradation mapping. I am applying following formula in ArcGIS 10.2-
("GW.img" * "LULC.img" * "Rain.img" * "Temp.img" * "Wind.img" * "NDVI.img" * "Livestock.img" * "Pop_Density.img" * "USLE" * "WEQ.img") ** (1/10.)
on the raster calculator. The final result is ranging from 4.1 to 8.5. But this map having various blank patches with no value. I am quite dubious about the way i am applying formula in raster calculator. Please, suggest me the right way to do it.
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Which software are you using?– ArMoraerMar 13, 2016 at 9:11
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ArcGIS 10.2– prash_geo87Mar 13, 2016 at 9:15
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What error are you getting?– alphabetasoupMar 13, 2016 at 9:44
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In a repeated attempt, Now I got a final map, which result is ranging from 4.1 to 8.5. But this map having various blank patches with no value. I am quite dubious about formula which I have used for Geometric mean calculation.– prash_geo87Mar 13, 2016 at 10:59
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If you are dubious about the formula then where did it come from?– PolyGeo ♦Mar 13, 2016 at 11:43
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1 Answer
My guess is that you have NoData or Null values in one or more of your input rasters.
As described in the Esri help page NoData and how it affects analysis, the presence of a NoData value in any of the input rasters can result in NoData in the output raster for some operators. This is definitely the case for the multiply/times map algebra operator, as shown below:
If my hunch is right, you will want to use the con() and isnull() map algebra operators to properly fill in the NoData values, as described in this GIS.SE question: Dealing with NoData in ArcGIS Spatial Analyst?.
