I have precipitation data from NOAA in a NetCDF format. I imported that into ArcGIS as a raster layer. Now I see that I can only get the precipitation value for one year at a time.

I need to calculate the annual average precipitation for the decade (1980-1990).

Is there any way to do this?

I am very new to GIS and don't know how to use Python. I have dabbled with the ModelBuilder a bit.


Assuming that you can get each year as a separate raster, do so. Then use ArcToolbox > Spatial Analyst > Local > Cell Statistics to compute a new raster whose cell values are the mean of the precipitation values at corresponding locations in all the other one-year rasters.


There are several ways of doing this, and probably by now you have already solved it. In case you haven't, I would make use of GDAL.


Just open a terminal on a machine that has gdal installed, and type in:

gdal_calc.py -A yourNOAAfile.nc --A_band=1 -B C:/yourNOAAfile.nc --B_band=2 -C yourNOAAfile.nc --C_band=3 --outfile=Avergage.nc --calc="((A+B+C)/3)"


In case you are not familiar with commandline tools and prefer a more ArcGIS solution, have a look here. Basically you either make use of the raster calculator or the cell statistics function.


And the QGIS alternative with a very sweet tutorial by Gregory Giuliani.

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