I am using ArcMap 10.3.
I am trying to create a new raster from 12 pre-existing rasters using the Raster calculator and I am having some trouble. You see, I want to create a new raster that represents the Precipitation Concentration Index, which uses the following formula:
PCI = (Summation (p^2) / (Summation (p)^2)) * 100;
where p = monthly precipitatoin average
I have all the rasters for world precipitation means by month, and hence I am using the following formula on Raster Calculator:
((("prec_1" ^ 2) + ("prec_2" ^ 2) + ("prec_3" ^ 2) + ("prec_4" ^ 2) + ("prec_5" ^ 2) + ("prec_6" ^ 2) + ("prec_7" ^ 2) + ("prec_8" ^ 2) + ("prec_9" ^ 2) + ("prec_10" ^ 2) + ("prec_11" ^ 2) + ("prec_12" ^ 2)) / (("prec_1" + "prec_2" + "prec_3" + "prec_4" + "prec_5" + "prec_6" + "prec_7" + "prec_8" + "prec_9" + "prec_10" + "prec_11" + "prec_12") ^ 2)) * 100
As a result, I was expecting something like this:
But instead I got this:
I have tried changing the symbology of the raster layer to "Streched" and adjusting the values to a suitable scale (they range between 0 and 50) following the example of the monthly precipitation layers - but then the map is just blank.
Anyway, since I do not know much about coding, I was hoping someone could help doing this the simplest way possible.
This is the exact message I got from ArcMap:
Messages
Executing: RasterCalculator "((("prec_1" ^ 2) + ("prec_2" ^ 2) + ("prec_3" ^ 2) + ("prec_4" ^ 2) + ("prec_5" ^ 2) + ("prec_6" ^ 2) + ("prec_7" ^ 2) + ("prec_8" ^ 2) + ("prec_9" ^ 2) + ("prec_10" ^ 2) + ("prec_11" ^ 2) + ("prec_12" ^ 2)) / (("prec_1" + "prec_2" + "prec_3" + "prec_4" + "prec_5" + "prec_6" + "prec_7" + "prec_8" + "prec_9" + "prec_10" + "prec_11" + "prec_12") ^ 2)) * 100" C:\Users\Documents\ArcGIS\Default.gdb\rastercalc
Start Time: Tue Feb 11 10:56:15 2020
(((Raster(r"prec_1") ^ 2) + (Raster(r"prec_2") ^ 2) + (Raster(r"prec_3") ^ 2) + (Raster(r"prec_4") ^ 2) + (Raster(r"prec_5") ^ 2) + (Raster(r"prec_6") ^ 2) + (Raster(r"prec_7") ^ 2) + (Raster(r"prec_8") ^ 2) + (Raster(r"prec_9") ^ 2) + (Raster(r"prec_10") ^ 2) + (Raster(r"prec_11") ^ 2) + (Raster(r"prec_12") ^ 2)) / ((Raster(r"prec_1") + Raster(r"prec_2") + Raster(r"prec_3") + Raster(r"prec_4") + Raster(r"prec_5") + Raster(r"prec_6") + Raster(r"prec_7") + Raster(r"prec_8") + Raster(r"prec_9") + Raster(r"prec_10") + Raster(r"prec_11") + Raster(r"prec_12")) ^ 2)) * 100
Succeeded at Tue Feb 11 11:03:31 2020 (Elapsed Time: 7 minutes 16 seconds)
