Mapping sub-surface strata

Hunter GeophysicsHunter Geophysics Global Mapper UserPosts: 75Trusted User
edited April 2010 in Technical Support
Is it possible to map individual strata beneath the ground using Global Mapper?

(i.e., I'll start off with a DEM that I will create using an RTK GPS, but then want to define layers beneath the surface, mapped also with the GPS after excavation). I tried creating an area feature with attribute Height less than the height of the DEM, but there is no way of 'peeling back' the layers that I can find, and so doesn't display that a particular area feature (layer) is beneath the ground.

Thanks for any help that may be rendered.

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2010
    David,

    If you have areas with negative relative heights or absolute heights beneath the loaded terrain surface you should be able to bring up the 3D display and see those 3D areas in space below the DEM surface. You need to bring up the options dialog in the 3D view and make sure that you have 3D vector display enabled and have the proper setting for the 'heights relative to ground' option.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Hunter GeophysicsHunter Geophysics Global Mapper User Posts: 75Trusted User
    edited April 2010
    Thanks for that, Mike. Got it working.

    Is there a way of defining a strata's maximum depth, i.e. the thickness of a layer? At this stage, I have

    HEIGHT = -1 metre

    which displays correctly, but the layer continues down to infinite depth (presumably to sea level), whereas I'd like to define layers beneath that one.


    In attached surface.jpg, yellow and white areas are HEIGHT = -1 metre, and black area is -2 metres. Subsurface.jpg shows that the yellow and white layers don't stop when the black layer starts.

    Thanks again. :)
  • Frank2Frank2 Super Moderator Posts: 105
    edited April 2010
    See if that problem goes away if you use the most recent build.
    32-bit - http://www.globalmapper.com/global_mapper11.zip
    64-bit - http://www.globalmapper.com/global_mapper11_64bit.zip
    Download the correct file, and extract the contents into your existing v11.xx installation folder to give it a try.
  • Hunter GeophysicsHunter Geophysics Global Mapper User Posts: 75Trusted User
    edited April 2010
    Thanks. Will give that a try.
    I'm on a 4kbps connection, so will let you know how it goes in a week. :D
    Cheers.
  • Hunter GeophysicsHunter Geophysics Global Mapper User Posts: 75Trusted User
    edited April 2010
    Na, that didn't fix it, sadly.
    Do I need to add a specific attribute to the area to define the thickness? I have minimal experience with attributes; is there a list of them available somewhere?
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2010
    David,

    You should be able to add an attribute with the name 3D_EX_HT with a value equal to the desired height of the area feature, like say '5' to make the feature have a thickness of 5 meters.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Hunter GeophysicsHunter Geophysics Global Mapper User Posts: 75Trusted User
    edited April 2010
    That's done it! Brilliant! :)
    Thanks.

    Is there a list of possible attributes somewhere?
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2010
    David,

    The bottom of the 3D viewer help page at http://www.globalmapper.com/helpv11/Help_3DView.html lists the supported attributes.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
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