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I have a raster layer representing land cover which has three categories of pixels: natural, semi-transformed and transformed.

I have a polygon feature class where each polygon delineates a catchment area.

I would like to calculate the proportion of each of the land cover types in each polygon. For example: I would like to know what percentage of each polygon is natural, semi transformed and transformed. I would like this information to be contained in the attribute table of the polygon feature class.

I am using ArcView License, ArcMap 10.0. I have the 3D Analyst Extension but not Spatial Analyst.

  • Unfortunately, the tools to do this analysis don't exist in the toolbox you have available. Given that ArcGIS 10 has been retired, you can't even add Spatial Analyst to your current product. – Vince Sep 27 '16 at 10:48
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Since you dont have Spatial Analyst you cant peform Zonal Statistics which would solve your problem. One solution is to convert the raster to Points and then perform a spatial join and summary statistics:

  1. Convert raster to Points with Raster to Point
  2. Join the catchment areas to the Points with Spatial Join
  3. Count the number of Points (=pixels) per type and catchment area with Summary Statistics. Then calculate the areas by multipling with pixel size.

Or you can convert the raster to polygons with Raster to Polygon, perform an Intersection with the created polygons and the catchment areas and then perform a summary statistics

  • Thank you for this. Unfortunately I cannot run the Raster to Point tool. ArcMap crashes every time I try to run it. I suspect that the problem is that the raster covers an area 16.8 million hectares in extent, and each raster pixel is 30 metres by 30 metres (0.09 hectares). Perhaps the processing required is too intensive for my PC. – Thomas King Sep 27 '16 at 14:34
  • Ok try my second suggestion and convert raster to polygon – BERA Sep 27 '16 at 15:13
  • Unfortunately it's the same problem. Computer crashes during the conversion. – Thomas King Sep 30 '16 at 7:15
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You can use the Tabulate Area tool to build the table of areas then join the resulting table back to your catchment data.

If your catchment areas overlap then not sure how this tool resolves that (either double counts or uses a single overlap), so you need to check for that situation.

  • 2
    But Tabulate Area requires Spatial Analyst which the OP doesn't have. – ahmadhanb Sep 27 '16 at 10:35
  • Ah! good point that will teach me for not reading to the end of the sentence! :) – Hornbydd Sep 27 '16 at 10:36

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