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I am using QGIS (2.10) to make a growing zone map of the U.S. from some data I found online. I need to reshape to fit into a U.S. map, and I find it's easier if I break the shape into smaller parts, and run an intersect on the smaller part with the map of the U.S. that I have (takes less processing time to do this, then merge the smaller with the larger after). The problem is that it will not let me break the shapefile, because it is an "Invalid Geometry". I have brought it into GRASS and have used v.clean, to no avail.

Is there a function that will actually tell you why the shape is an invalid geometry, or can someone tell me how to purge the invalid geometry demon?

I do not see how to attach a file to this post or I would have attached the shapefile.

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    Welcome to GIS:SE @TheShawn! You can try using the Check Geometry Validity... from the toolbar: Vector > Geometry Tools > Check Geometry Validity.... There's also a more advanced plugin called Geometry Checker but I think this is only available from QGIS 2.12 onwards. Although you can't upload attachments to Stack Exchange forums, you can upload files to a public server (e.g. Dropbox) and include the link in your post =)
    – Joseph
    Mar 21, 2016 at 14:57
  • Thanks Joseph. Here is a link to the shapefile data: drive.google.com/file/d/0B2-ILN-LS5WmVnNjSlFJRl9Jd0U/…
    – The Shawn
    Mar 21, 2016 at 16:51
  • ArcGIS's Check Geometry tool complained about a missing spatial index, but once that was added, didn't find anything else.
    – mkennedy
    Mar 21, 2016 at 17:28
  • QGIS "Check geometry validity" tool doesn't search any errors.
    – Artec
    Mar 21, 2016 at 17:53

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If possible , try other tools to check the geometry. I checked your file in Geomedia.Look at this picture below, probably there is a problem with your shapefile.

enter image description here

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  • Artec, That was the issue! Thank you for the help. I am going to try the file in QGIS 2.12 to see if it catches this issue.
    – The Shawn
    Mar 21, 2016 at 19:48

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