Global Mapper v25.0

Missing area feature when exporting vector data

Tom Lee
Tom Lee Global Mapper User
edited July 2007 in Bug Report
I load a SRTM3 DEM data file named N34W119.hgt.zip (ftp://e0srp01u.ecs.nasa.gov/srtm/version2/SRTM3/North_America/W119N34.hgt.zip).
When I generate contours with the 50 meters intevals and enable the area generation checkbox, I find the a 50-meter area close to the bottom is missing despite that the contour line is correctly generated.

The version that I use is the latest trial version 8.0.3.

Comments

  • global_mapper
    global_mapper Administrator
    edited June 2007
    Tom,

    Thank you for your bug report. I tried myself and was able to reproduce your problem and get it fixed. I have placed a new build at http://www.globalmapper.com/global_mapper8.zip with the fix for you to try. Simply download that file and extract the contents into your existing v8.xx installation folder to give it a try.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Tom Lee
    Tom Lee Global Mapper User
    edited July 2007
    Hi,

    Thanks for the quick fix. I tested on N34W119. It works.
    However when I tested on another tile N45E007 from the
    SRTM3 dataset. It fails to generate all the area features again.
    The relatively flat area in the bottom right part of this tile.
    The height intervals that I've tried are 50, 100, 200. They all
    don't work.

    Also notice that there are a lot of holes in the original raster DEM.
    However, I don't think this is the cause of the problem.

    -Tom.
  • global_mapper
    global_mapper Administrator
    edited July 2007
    Tom,

    Actually what is causing the trouble is the no data areas along the edges at the top left. Because the no data is along the edge the gap filling is unable to fill them. In some cases this causes trouble trying to close the contour areas, so they can't be created successfully.

    What I would suggest doing is using the free 90-m SRTM data with the holes filled from CGIAR at http://srtm.csi.cgiar.org/ to generate your contours, or at least load that data before your other files so that it can be used to fill the gaps. With the gaps filled you should not have any trouble.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com

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