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Currently doing a final project for school on ARCMAP 10.

I have a set of unsuitable and suitable buffers over a big area which is Quebec City, Canada. The final potential sites give me areas between 900 sq meters and over 33,000,000 sq meters. We want to keep areas between 500,000 and 1,000,000. The problem is that some polygons become too thin in certain areas. So, although a polygon is big enough in area, in some spots it is too narrow for all the infrastructure we need.

Any help would be much appreciated. Thanks

enter image description here

(Original at http://postimage.org/image/ftwsumkt1.)

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Could you possibly provide a graphic or screenshot to illustrate this problem a little more clearly? –  AHigh Aug 23 '12 at 16:00
    
I see that you are also working with a DEM and, from the blockiness of the polygons, it seems they might have originated in a raster format. Is this the case? Do you have access to Spatial Analyst or other raster-based GIS software (like GRASS)? (If so, it will provide some efficient and powerful ways to identify the suitable buffers.) –  whuber Aug 23 '12 at 17:49

2 Answers 2

Not sure there is a scientific answer to this. You may need to reword your question - the perimeter length will still be high in the area you highlighed on your graphic as well as the area. I assume you mean "usable area" i.e. you can't fit buildings on a very thin footprint of land.

So that said, the only thing I can suggest you do would be to calculate the area of the minimum width bounding box or convex hull for each object(try here), and then compare that to the area of the shapes themselves. Then you need some of cut-off ratio - for instance if the area of the bounding shape is much larger than the area of the shape itself, that would suggest you may have a strangely shaped object with potentially some thin sections. On the other hand, it still may not find very thin, linear objects (although these seem unlikely given the way you have derived the suitable areas).

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Thank you for all your help.. Unfortunately I am doing an intensive/beginner GIS class at University. We did this class in 15 days instead of 14 business weeks =_=. I only had 2 days to complete this project, and with a 5PM deadline, 7 hours ago, I simply chose polygons within a certain area, carefully planning which ones would be left, insuring they were only square-ish ones, if that makes any sense.

I will surely make use of this help site if I chose to do the advanced class =)

I can show my final map if it is of any interest to any of you. If not, til next time!

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