Global Mapper Pro

volumetric features

energy
energy Global Mapper UserTrusted User
edited February 2013 in Technical Support
Hi
I'd open the discussion in elevatin data(calculating volumes of gravel piles) but I dont want a confusion.
I am a bit confused by "measure volume" option, for siplicity I begin to ask simple

1-there is not a elevation data I have just area features, forexemple I have a square , I add one value or one by one value for each vertices as elevation(vertices) , I try to "calc attr" but new attribute=enclosed area*???(there are not elevations as attribute(s))how can I measure the volume?

2-the sguare on the a dem or grid file; rigt click ,choose measure volume. I havent seen "above ground" also "specify the base height to use at each vertex" option is inactive????

3-When I used test the "above sea level" fill volume is zero, I dont understand what is diferrence between cut volume and fill volume??

Thanks...

Comments

  • global_mapper
    global_mapper Administrator
    edited February 2013
    You have to first add the measure attributes, they aren't automatically there for features. You can do this by selecting the features in the Digitizer Tool, then right-clicking and selecting the Measure submenu command to add measure attributes.

    For area volumes the volume currently has to be measure relative to a flat surface cutting through your loaded terrain. So for a building top you could specify the height as say 10 meters above ground, then the fill volume would be everything above the terrain and below the cut surface. The cut volume would be everything below the terrain and above the cut surface.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.bluemarblegeo.com/
  • energy
    energy Global Mapper User Trusted User
    edited February 2013
    firstly; I am using 13.2. Mike ,when I right-click "add mesure attribute" it add only enclosed and permiter area, there is any volume measure as attribute? for exemple I have a square that is 5000m2, I add the same or diferrent elevation(heights) to its corner(vertices) , I'd like to measure this body volume, is it possible?? I give another exemple, there is a video which is named "viewing 3d vector" data in the tutorials, can I measure the buldings volume in the video?

    secondly; I dont understand exactly differences:( I sent a picture

    prs.jpg
    prs.jpg 422.7K
  • global_mapper
    global_mapper Administrator
    edited February 2013
    There isn't a single "volume" attribute that would apply for an area, the volume would be relative to some terrain surface. The volume calculation to have a different height at each vertex if for getting the volumes of a corridor along a line feature (like a pipeline) and doesn't work for area features. Only single height area volumes are directly supported.

    If you have a full 3D area you can create a terrain surface from it using the Advanced Feature Creation submenu option in the Digitizer Tool, then use the Analysis->Measure Volume Between Surfaces menu command to measure the volume between that new surface and the base terrain.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.bluemarblegeo.com/
  • energy
    energy Global Mapper User Trusted User
    edited February 2013
    Ok Mike I am cofused, I think cut volume is from sea level(or another level) to terrain surface; fill volume is from terrain surface to height of the line. Calculate volume diferrent methods in GM;

    1-from polygon area(voronoi diagrams) 2- Analysis->Measure Volume Between Surfaces 3-The reason I ask questions above ,I am wondering calculate volume from thickness maps(isopach maps) ,its contour value is height value at the same time .
  • global_mapper
    global_mapper Administrator
    edited February 2013
    For area features it is relative to a single cut plane. The volume along lines is more capable as it can have different elevations for each vertex of the line. The Measure Volume Between Surfaces is the most advanced as it allows any Z values at any location. If you can make a new surface from your areas then you can do the volume.

    Thanks,

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