Free Elevation data sources inside GM

global_noobieglobal_noobie Global Mapper UserPosts: 15Trusted User
edited May 2014 in Elevation Data
Is it possible to get a list of the most accurate FREE ELEVATION DATA that can be streamed inside GM?
Most of the links I open in the presets end up freezing or timing out.

Surely there must be one or two sources which are the most accurate and that should render most of the other sources redundant?

If so could someone please post them. I'm still on global mapper 12 so hopefully this is still new enough to stream them.

Thanks

Comments

  • global_noobieglobal_noobie Global Mapper User Posts: 15Trusted User
    edited April 2014
    ok the best I found so far is here.

    *****TERRAIN DATA*****

    + United States Elevation Data (NED) (10m Resolution)
    + SRTM Worldwide Elvation Data (3-arc-second resolution)

    Helps a lot if you define the initial area with a radius too.

    If anyone has any better FREE sources then please let me know, I do use some paid solutions for small areas, too bad the people that sell this data are so greedy, if they made it more affordable I'm sure a LOT more people would be doing some cool things with it on a large scale.

    For the price of 5000 square metres in the UK for 1m lidar data its over £1200. And this is data that's 6 years old so its all been collected, just seems odd these people would rather rip off a academics and government types, instead of making it more accessible to more people.

    As it stands I am trying to get the best free stuff I can and see how its comparing to the paid data I bought and whether I do anything to do that data to someone interpolate more accurate detail via additional software. So if it is possible to do anything to existing elevation data to make it appear more accurate (even if the process is a little long winded) I am all ears.

    /Rant Over :)
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2014
    The NASA/JPL server which provides some of the streaming sources, ASTER GDEM in particular, has been down for a couple of weeks. We are working on getting that data ourselves so we can stream it out (including a newer version), but the SRTM source coming directly from our server is fine. There are also links in v15 directly to a web site where you can get the ASTER GDEM v2 data for small areas.

    For the US the USGS 1/3rd arc second is great and covers the entire country, but outside of the US it is much harder to come by high quality data for free.

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation
  • kenjinkenjin Global Mapper User Posts: 7
    edited April 2014
    Hi.
    I need DEM data before 2005 year and next years. I can download in GM but I dont know what date is. I want to measure volume of small area before 2005 and after 2005. Can ı use srtm 3 arc-second data and srtm Gdem 1,5 arc-second data. I think 3 arc-second data date is 2003 and Gdem data date is 2011. Anybody help please.

    Thanks.
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2014
    The SRTM data was all collected at once back in 2003 I believe. The ASTER GDEM is newer. You could use those for volume calculations for large areas with big height differences, but I wouldn't use it for anything less than a square kilometer or so due to the low resolution of the data.

    For measuring accurate volumes of piles of material you almost need Lidar-derived data, but you wouldn't be able to get older high-resolution terrain for most areas.

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    Global Mapper
  • kenjinkenjin Global Mapper User Posts: 7
    edited May 2014
    Thank you Mike.
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