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I have a raster file with 5 classifications developed from habitat modelling algorithms. I'd like to know how much of 2 classes of the raster is covered by the network of protected areas (Shape file). Could any one advise me how to do so?

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2 Answers 2

up vote 5 down vote accepted

I would recommend clipping the raster to the shapefile, then in the resulting raster you can look at the number of cells present for each of your classes. The area can be calculated by multiplying the number of cells by the area covered each pixel (cell size squared).

It's a different approach than the equally valid solution offered above but from a slightly different angle. A little variation never hurts!

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+1 I'd overlooked that "network of protected areas" might just need "in or out" –  PolyGeo May 2 '13 at 23:00
    
I need to know how much of my suitable patch is covered by protected areas. –  Mahdieh Tourani May 3 '13 at 9:07

This can be accomplished using three main steps:

  1. Convert your raster to polygons using the Raster To Polygon tool

  2. Overlay your polygons (from raster) with your shapefile using the Intersect tool or Union tool - which depends on how many polygons you want output

  3. Tabulate your results using the Summary Statistics tool (or perhaps the Tabulate Intersections if you have an Advanced license)

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(+1) But when the raster is messy--and many real landcover classification rasters can be--it is far faster (and requires less RAM) to go in the other direction and rasterize the polygon, overlay that with the original raster, and read off the areas from the attribute table. –  whuber May 2 '13 at 22:18
    
I tend to have a vector mindset but here is where making raster the common data format might make a lot of sense. –  PolyGeo May 2 '13 at 22:31
    
Thank you for your reply. Actually my extent is so large containing a lot of data in attribute and it is difficult to read them. –  Mahdieh Tourani May 2 '13 at 22:48
    
just a question; in step 3, Summary statistic tool needs statistic field and case field. which field should be chosen to come up with the favored result? –  Mahdieh Tourani May 3 '13 at 13:05
    
I recommend that you experiment to learn more about the tool or alternatively provide details about the fields you are using in your original question. –  PolyGeo May 3 '13 at 20:32

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