Crop tool enhancement - easely spot removed areas?

RobertRRobertR GlobalMapper Fan!Posts: 286Trusted User
edited September 2012 in Suggestion Box
Hello all,

I am using a lot the "Crop Loaded Features to Selected Area(s)" and often I encounter a problem (or even two):

- "one or more features is/are invalid and cannot be.."
- the number of features in the new created layer is smaller than in the original file (no error message).

Now, the problem is that I use state-wide data and it is very difficult to find the ones that are removed (sometimes I see even large areas completely removed and not split). I know that we used to take a big advantage of a difference tool in another software to find out parts of la polygon layer that are not present in another layer.

I need to crop some polygons that spread through more than one county in order to give each cropped part the county id. And often it does not work out quite well.

Is there a way to fix this? Some enhancement to this Crop Tool maybe?

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited September 2012
    We are planning an enhancement (likely in v14.1) for automatically finding and fixing invalid (i.e. self-intersecting) polygons so that the polygon crop tool can handle them. We also may switch to a different library altogether for the polygon crops themselves as the library that we use is full of problems if your data has any strangeness at all. It is also rather slow in many cases.

    For coverage checking, could you make one layer one solid color and another layer a different solid color, then maybe export to a raster file (like a GeoTIFF) of high resolution, then load that back in and right-click on the GeoTIFF layer and select to create equal-value areas of the color of the bottom layer. Any areas created would be non-covered parts from the bottom layer.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
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