Digitizing many points

PSUJimPSUJim Global Mapper UserPosts: 12
edited July 2011 in Technical Support
I'm currently using a shapefile of an outline of a country (a very large area). I have overlaid this shapefile on top of a scanned/geo-rectified map of the precipitation levels for the same country. The shapefile matches up well with the scanned map's borders, and now I'm in the process of digitizing the interior of the country based on the scanned map's precipitation breakdown.

Because the borders are (relatively) identical, the parts of the precipitation map that run into the border of the country will, obviously, share the same points as the initial shapefile. The problem is that the shapefile is fairly detailed, with thousands of points for the country's border. Is there a quicker way to include portions of these points as part of my area digitizing, without having the manually snap to each vertex? Can I select a group of points to include as part of a new area and then continue digitizing from the last of those selected points?

Any help is much appreciated.

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2011
    What I would suggest is drawing your areas that are on the borders to go outside the border at the first intersection point, then come back in at the last intersection point. Then you can just crop your precipitation area to the country boundary and they should match up perfectly.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • PSUJimPSUJim Global Mapper User Posts: 12
    edited July 2011
    Hey Mike,

    I have tried your suggestion, but perhaps I'm missing something. When I open the control center and select the Options button, I do not see the cropping option for any of the layers that are vector data (I only see it for raster data). Is there another way to crop?
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2011
    You would need to crop on export by selecting the country boundary, then on the Export Bounds tab of the export dialog selecting to crop to the selected area. Then your areas should be cropped to the country boundary on export.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2011
    You could also crop by finding the intersection of the areas using the Digitizer Tool. SEe http://globalmapper.com/helpv12/Help_DigitizerTool.html#intersect_areas for details.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • PSUJimPSUJim Global Mapper User Posts: 12
    edited July 2011
    Hey Mike,

    Your first suggestion wasn't working; the program freezes when I try to export with the area cropped to the selected feature (i.e. the country).

    However, your second suggestion proved somewhat successful. Once I find the intersection, I still have the area that is 'outside' the country's border. But I can select this area and delete it, leaving the remaining interior portion of my digitized area.

    Not sure if this is what you had in mind with the second suggestion, but it worked. Thanks, Mike!
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