Global Mapper v24.0

can't add elevation to line segment

JSL
JSL Global Mapper UserTrusted User

I'm trying to use line segments to create buffers from which I can build dams using the Create Terrain process, but I can't get to the first step of adding elevations to the line. Attached is a workspace containing a line segment and a DEM. When I try to "Apply elevations to selected features", it says "Elevations updated," but no attributes were actually added:

Thanks for any help.

Answers

  • hennie
    hennie Global Mapper User Trusted User

    Perhaps if you export your workspace as a GM Package file may we be able to recreate the elevation grid. Presently only the line appears in your workspace file.

  • BMG_Amanda
    edited January 4

    With line and area features, Apply Elevation assigns the elevation values to the vertices. Line features have multiple vertices, each with their own elevation value, so Global Mapper can't display it as a single attribute. To see the elevation/Z values, click the Vertices button near the top of your Modify Feature Info dialog.

    For other uses with the same question, here is information on that dialog: https://www.bluemarblegeo.com/knowledgebase/global-mapper-24/Modify_Feature_Info.htm

  • JSL
    JSL Global Mapper User Trusted User

    Here's a package file:


    My goal is to use a single line segment to create a buffer from so as to generate a dam using the create terrain or flattened site plan processes, as in the first example in the GM knowledgebase article on adjusting elevations to a single slope (https://www.bluemarblegeo.com/knowledgebase/global-mapper-24/modify/Adjust_Elevations_to_Slope.htm?Highlight=slope; https://www.bluemarblegeo.com/knowledgebase/global-mapper-24/Creating_a_Flattened_Site_Plan.htm)

    I know the segment has vertex elevations, and when I try to use the "Adjust Elevations to a Single Slope" process to set the slope to 0.0, it says that the slope was modified, but when I then generate a 1 km buffer and try to use the Create Terrain command, I get the message that the area feature doesn't have elevation values associated with it. Using the create flattened site plan command doesn't result in anything. So how did the 2-vertex segment in the knowledgebase article get an elevation value?

    Thanks for any help.

  • hennie
    hennie Global Mapper User Trusted User

    Is the attached image more or less the result you are looking for?


  • hennie
    hennie Global Mapper User Trusted User

    I am way too lazy to describe my workflow. I attach a pdf document with screenshots to show what I did.

    Note that I have GM 20 on this PC. Wording, menus, etc may differ from your GM 24, but the tools are similar.

    Hope this helps!


  • JSL
    JSL Global Mapper User Trusted User

    Thank you very much! That result is exactly what I'm looking for. How did you get the 1760.272m elevation for the buffer? I can't get an elevation for the line segment when I try to apply elevations to it. I ended up creating a buffer from the line segment, calculating the elevation/slope stats for the buffer, attributing the maximum elevation to a new attribute of ELEVATION, then using your Create Flattened Site Plan process, and got a perfect dam (see below). I just wish I could make the process more efficient by getting an elevation for the line segment before I create the buffer.


  • hennie
    hennie Global Mapper User Trusted User

    Hi,

    I got it from the Feature Vertices of your line, as per attached workflow.

    Regards

    Hennie


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