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I have different bigger polygons (buffers) which are overlapped (A,B,C,...) and the inner smaller ones (a,b,c,...). I want to erase smaller ones from bigger ones in the way the results be A-a, B-b, C-c, ... . If I use erase it erases smaller ones from all of overlapped bigger ones. Do you know how I can fix it?

My software is ArcMap 10.

  • I need to remove smaller polygons just from their corresponded bigger polygon. But because there is overlap between bigger polygons when I use erase, it subtract small polygons from different bigger polygons. I need a way to subtract corresponded polygons from each other. – pegi Jun 16 '16 at 8:30
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    Select your matching polygons first, then run the erase. Erase will honour selections. If you've got a lot of them, you will probably need to use model-builder or python to iterate through them all. – Midavalo Jun 16 '16 at 9:02
  • @Midavalo I did not work with model-builder and python before. but maybe this is the solution! – pegi Jun 16 '16 at 16:35
  • The problem is because the radius of my bigger buffers is 5000m and the radius of smaller ones is 50m, using erase results to subtraction or erase of more than one smaller buffer from a single bigger buffer. However, I need that just the center buffer remove from a single bigger buffer. – pegi Jun 16 '16 at 16:41
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Solution that works if your small polygons do not overlap:

arcpy.Union_analysis("small #;large #","C:/FELIX_DATA/SCRARCH/SCRATCH.gdb/UNION","ALL","#","GAPS")
arcpy.SelectLayerByAttribute_management("UNION","NEW_SELECTION",""""Name" = "Name_1"""")
arcpy.DeleteFeatures_management("UNION")
arcpy.Dissolve_management("UNION","C:/FELIX_DATA/SCRARCH/SCRATCH.gdb/UNION_Dissolve","Name_1","#","MULTI_PART","DISSOLVE_LINES")

enter image description here

  • Thanks for your answer, It was not practical but I found the answer. – pegi Jun 20 '16 at 12:22
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The answer is defining the bigger buffers as disks (outside buffers around and outside the small inner ones that does not include the inside area of inner buffers), each bigger buffer will have specific inner ones and the overlaps of bigger buffers is not important. So, easily we must follow the process of buffer making from small ones to bigger ones.

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1) In Geoprocessing, use the Union tool to create a single feature class. This causes a "cookie-cutter" effect on overlapping polygons.

2) Start editing on the newly created feature class, exported from the Union.

3) Delete the desired polygons.

  • This is not practical because I need separate bigger buffers which have erased inner polygons as result. I need this buffers for my zonal analysis. – pegi Jun 16 '16 at 16:33

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