Global Mapper Pro

elevation data

wmiswm
wmiswm Global Mapper UserTrusted User
I have elevation data from "spot height", "contour line", and "inland lake surface polygon". I understand that I can use the control center option and assign elevation from the appropriate attribute. I wish to ask, can I use the elevation data of all these three types, viz line, point, and polygon, to generate a dem directly without further processing?

Best Answer

  • Katrina
    Accepted Answer
    To create a DEM from points, lines and polygons with assigned elevation values, go to Tools> Create Elevation Grid from 3d Vector Data...
    This will allow you to choose any vector layers that have an identified elevation or height value. This operation uses a Triangulation Network (TIN) to generate an elevation surface using the vertices of every feature. With the Lidar Module you also have the option to use Binning to generate the elevation surface, 

    To apply the elevation value to the entire polygon rather than just the vertices, check the 'Flatten 3d Area Features' option. 

    If you would like further suggestions f settings to use for a specific data set, you can reach us at geohelp@bluemarblegeo.com and provide a sample of your data. 
    For more information on this tool check out our help documentation here: http://www.bluemarblegeo.com/knowledgebase/global-mapper/Content/Create_Elevation_Grid_from_3D_Vector_Data1.htm

Answers

  • wmiswm
    wmiswm Global Mapper User Trusted User
    After a few trials to generate DEM, I am still confused with how GM will make use of the elevation data from "contour line" and "polygon" with elevation data for the triangulation process. The DEM outputs seem to have "lower resolution" than the original data, and the "polygons" are not always flat as specified by the elevation of the polygon. One further issue is that, at the junction of polygons of the same elevation, some mysterious ridges were generated. Is there any recommendations for DEM generation in such scenario?
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