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How can I use SRTM/elevation data for vector

geospheregeosphere Global Mapper UserPosts: 3
edited January 2015 in Elevation Data
Hello everyone,

I will shortly present my goal: I want to create a 3D model of section of a city.
So far the buildings, parcels etc. are digitized, however they do not have any Z/elevation data. Here comes, my question: how could I add height value to vectors using SRTM or ASTER or LIDAR anything with some decency in terms of accurate height values? Is there any way that I could just extract or do some divison or something to get those values for each vector layer in part?

I'm pretty much a GIS and Global Mapper newbie, thus I could use some help.

Best wishes,

Comments

  • Josie_BMGJosie_BMG Global Mapper User Posts: 71
    edited December 2014
    Hi Geosphere, you can select you area features (right-click on the Vector feature layer in the Overlay Control Center, then choose Select All Features in Selected Layer with the Digitizer Tool), then choose the Digitizer tool and right-click on the map, go to Attribute/Style Functions > Apply Elevations From Terrain Layer to Selected Features.

    Hope this helps!
    -Josie
  • geospheregeosphere Global Mapper User Posts: 3
    edited December 2014
    Hi Josie,

    Thank you for giving me a solution. I'll apply and see how the results are.

    Cheers.
  • geospheregeosphere Global Mapper User Posts: 3
    edited December 2014
    My first attempts, I've used ASTER GDEM v2 for this work.
    The thing is, it's quite far from reality but for now I'm just testing.

    attempt1.pngattempt2.pngzoom-attempt2.png

    Although, I applied what you suggested Josie (and it worked, the elevation data got updated quite nicely), as I go on another question appears. How could I get the real values elevation of the buildings, tramway etc? Is that possible, some sort of divison between layers or any sort of algorithm?

    So far it doesn't look good.

    Best wishes,
    Florin
  • Josie_BMGJosie_BMG Global Mapper User Posts: 71
    edited January 2015
    Hi Geosphere, The instructions that I gave you will update the elevations of the vector data with the ground values. Your vector features look like they are set for the elevation values to be Relative to Ground, instead of Absolute, which means that the value is relative to sea level instead. You can update this at the bottom of the Modify Feature Info dialog box. The Aster data is just supplying ground elevation values, you would need to find an additional data source of surface terrain that includes the buildings to be able to apply the building heights to the area features. Has any Lidar data been collected in your area of interest?

    -Josie
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