2

I have a population dataset in raster format (each pixel has a value showing number of people in that pixel) and a polygon shapefile with 10 districts. What I need, is to calculate population for each district. I thought it would be easy but I'm having difficulties... I use ArcGIS 10.3. I tried to turn raster to polygon, so that every square resembles a pixel. Then I tried to spatially join the two shapefiles, However, the numbers are wrong.

  • 3
    Welcome. Please take the community tour here: gis.stackexchange.com/tour and update your question to include what software you are using as well as what exactly you have tried and what you are having problems with. What tools are you using? If using a script, please include part of your code. – MaryBeth Aug 11 '17 at 14:51
  • I agree with MaryBeth. This can be easily made, but depends on wich software are you using – aldo_tapia Aug 11 '17 at 15:35
  • Do you have the spatial analyst extension? – jbchurchill Aug 11 '17 at 20:26
  • Yes I do have the spatial analyst extension. – Manolis Aug 14 '17 at 12:36
1

It sounds to me like the Zonal Statistics tool will work for you. I typically use Zonal Statistics as Table because it is really the tabular values that I want most (rather than a raster with a calculated value for each zone).

I think that the specific statistic you want is the SUM since you would add up the population from each cell into the entire zone.

Set up your polygon "Districts" layer as the "Input raster or feature zone data" input and your population raster as the "Input Value Raster". Then designate an output table to store the values. You could leave statistics set to "ALL" or change it to "SUM" if you are certain that is all you need.

Sometimes as a second step you may find it desireable to do a tabular join back to the Districts layer and your tabular output from Zonal Statistics as Table is set up to do that for you by using an OID for FID field in the output that matches your Zones (districts).

Zonal Statistics as Table

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.