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wmiswmwmiswm Global Mapper UserPosts: 220Trusted User
edited October 2012 in Technical Support
I am cropping a big map to a specified area and returned with error. Please examine one of the examples I custom produced to illustrate this point. Please try to crop to the area specified by the T11 boundary area and see the error.

I am sending you the link of the file to your email gmsupport@bluemarblegeo.com, and I am using ver 13.2.2 b062012. Please take a look and see how this can be solved. Thank you very much.

Comments

  • wmiswmwmiswm Global Mapper User Posts: 220Trusted User
    edited September 2012
    Oh very sorry, I some how mistakenly filled the title but cannot edit it anymore. The title should be "Cropping Error".
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited September 2012
    The issue is that some of the areas that would be cropped are "invalid", typically meaning that they have self-intersections, and our polygon-to-polygon cropper does not like that. Since the area that you are cropping to is basically a rectangle, you can try just exporting to a new file and on the Gridding tab of the Export dialog select to grid to the selected areas. You can then choose to just crop to the rectangle of the area. The crop-to-rectangle function doesn't have any problem with invalid polygons so that will work fine. You can then bring the new file back in.

    We do plan to add more tools to find and fix invalid polygons in a future release, hopefully v14.1.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • wmiswmwmiswm Global Mapper User Posts: 220Trusted User
    edited October 2012
    Thank you very much Mike. Will it work if I crop to exact instead of choosing the crop-to-rectangle option, because I am not sure whether other boundaries are true rectangle or with an angle?
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited October 2012
    You would have the same problem as before if you did that, only you wouldn't see the errors. You would get all of your valid polygons cropped to the exact area, and any of the invalid ones just cropped to the rectangle bounds.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • wmiswmwmiswm Global Mapper User Posts: 220Trusted User
    edited October 2012
    I see, hope that the 14.2 solution will come out soon. By the way, the best thing is that GM provides a routine which can search for all "invalid" polygons, eg polygons with intersections or two points polygons, and "correct" these before crop or export.
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