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I am wondering if there is a way to easily split results of a disolved buffer into individual polygons? E.g in the screenshot below all of these buffers are one item, can I split them into individual items? I have Arc, MapInfo and QGIS.

enter image description here

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So you want to have four individual features, one for each circular buffer? Or do you want to split each circle into segments, using the roads as cut lines? –  Jake Oct 15 '13 at 12:04
    
Four individual features, however splitting using the roads may also be useful! (if possible) –  Alan Carr Oct 15 '13 at 12:07
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4 Answers

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If you run the Dissolve tool in Arc there is an option in the toolbox that creates multipart features. If you untick this the output of the dissolve will be 4 individual features.

enter image description here

You should then be able to do the same thing with the roads to split your 4 features down even further.

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In most GIS look for the process "Multipart to singlepart". This will break apart a multipart feature and make separate features of the constituent parts. I your example, you will end up with 4 separate polygon features. In QGIS go Vector->Geometry Tools->Multipart to singleparts. ArcGIS and MapInfo have similar tools (as does GRASS and pretty much any decent GIS I've come across).

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In ArcGIS, the "Explode" command (on the Advanced Editing toolbar) will do this. –  Dan C Oct 15 '13 at 16:21
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In QGIS you can use the MultipartSplit plugin to split selected polygons during an edit session without the need to create yet another shapefile.

If you need to also split the features using the roads, you can use Vector > Geoprocessing > Union with the splited polygons as input layer and the roads as union layer.

Hope it helps!

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And for MapInfo procedure is:

  • Select multi-part object

  • Objects/Disaggregate

enter image description here

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If you used MapInfo Professional to create the buffers in the first place, you could have chosen to create the buffers as individual buffers. That might however have created more than four buffers if you had selected more than four input objects. –  Peter Horsbøll Møller Oct 16 '13 at 14:18
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