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Vertical Datum Questions

terrasimterrasim Global Mapper UserPosts: 2 ✭✭
edited August 2012 in Elevation Data
I have a few questions about vertical datums and their support in Global Mapper.

1) Is there a way to view the vertical datum of a file in Global Mapper? I have only been able to find horizontal datum information.

2) Is there an option that can be turned on in Global Mapper so vertical datum information is written out in .prj files during export?

3) Does Global Mapper encode vertical datum information in the tags of a TIFF file?

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238BMG Staff
    edited July 2012
    There is only very limited vertical datum support currently in Global Mapper for a couple of formats (i.e. GeoTIFF, USGS DEM, Lidar LAS), and that is only for displaying and exporting the vertical datum and not converting between them. If you are using a file with that information and Global Mapper supports it, the value should show up on the Metadata dialog for the layer. If you export to a format that supports this and the vertical datum is one of a handful of known ones, this should also export to the file itself. The PRJ file export does not however support vertical datums.

    We do plan to add more vertical datum support in upcoming releases of Global Mapper, likely starting with the v14 release in a couple of months.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • terrasimterrasim Global Mapper User Posts: 2 ✭✭
    edited August 2012
    Thank you, that information is very helpful. Is there any documentation that lists the vertical datums that Global Mapper supports? I've searched the PDF version of the online help but didn't find anything. Perhaps I missed it somewhere though.
  • global_mapperglobal_mapper Administrator Posts: 17,238BMG Staff
    edited August 2012
    There isn't a list anywhere in the help since the conversions themselves aren't yet supported, but the GeoTIFF format currently supports the codes for NAVD29, NAVD88, and WGS84 ellipsoid height. There are a lot more codes supported in GeoTIFF itself but that aren't in GM yet. We plan on having some additional vertical datum support in a v14 release.

    Thanks,

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