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Thread: Terrain for your route

  1. #1
    Join Date
    Nov 1999
    Location
    Newark, Delaware
    Posts
    1,294

    Default Terrain for your route

    Here's a quick comparison of available digital elevation date and the quality of each.

    The first thee images show the visual quality of each in a mapping program:

    1) SRTM 3- smooth, but much important detail not visible

    2) SRTM 2- more detail but grainy do to ground clutter reflectance.

    3) DEM 1/3- Arcsecond smooth and copious detail including fills and cuts in valleys and on mountainsides.

    The next next 2 images show the results in the Railworks world editor.

    4) Terrain data from SRTM 3 date applied with the "T" key.

    5) Terrain data from DEM1/3as processed with the redem utility. Fills and cuts followed were already there when I started.

    SRTM data advantage is it can be applied directly without any additional processing. The Redem utility needs to know the route start point and route markers to "guide" its way through the known world.

    Personally, I'm not adverse to adding extra steps for better detail.

    Hank
    Attached Images Attached Images

  2. #2
    Join Date
    Nov 1999
    Location
    Littleton, CO, USA.
    Posts
    864

    Default

    You're right, Hank. Redem makes it look much better. I'm gonna need to look at that seriously.

  3. #3
    Join Date
    Nov 1999
    Location
    Penrith, Australia.
    Posts
    2,994

    Default

    Nice if you are modelling U.S. routes, unfortunately the rest of us are stuck with the SRTM 3 which although usable is really poor compared with what is available to U.S. users.

    Mike

  4. #4
    Join Date
    Dec 2005
    Location
    All Over the US
    Posts
    275

    Default

    dumb question,

    where do you get REDEM

  5. #5
    Join Date
    Nov 1999
    Location
    Stevens Point, Wisconsin, USA.
    Posts
    14,705

    Wink Smart Answer

    Try here; http://www.zugware.com/site/

    Being a sloppy slob who considers framerates and the fatware factor more important, which is the more COARSE .hgt to use?

    ftp://e0srp01u.ecs.nasa.gov/srtm/version2

    I got a couple SRTM1 files from there, DEMming a few dozen tiles bloats the route up to 50 megabytes just for the terrain. Should I be using SRTM3 or whatever if I'm going against the crowd and trying for a smaller download instead of smoothly rounded curves?

  6. #6

    Default

    Quote Originally Posted by downtrack View Post
    Edit: already answered by sniper
    When editing your message you can also delete it. Not if it is the first in a new thread.

    O t t o

  7. #7

    Default

    Thanks, i didn't know that. Deleted

  8. #8

    Default

    sniper,

    AFAIK, the number of terrain "polys" in RS/RW is the same regardless of the input DEM resolution. The terrain grid has a value every 8m which is interpolated from the *.hgt files (or other sources ).

    There are as many terrain data points in a square RW km of Kansas as there are in the Alps. This could change if RW ever develops "distant mountains" which might have a lower resolution.
    Jim - ZugWare!

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