Changes between Version 1 and Version 2 of TerrainData


Ignore:
Timestamp:
17/06/15 03:59:37 (5 years ago)
Author:
Olly Betts
Comment:

fix formatting; add known issues

Legend:

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  • TerrainData

    v1 v2  
    1010
    1111 * [https://en.wikipedia.org/wiki/Shuttle_Radar_Topography_Mission Shuttle Radar Topography Mission (SRTM)] - this is based on data collected by a NASA shuttle mission in 2000.
    12    It was originally released with a resolution of 1 arc-second (about 30m) for the USA and 3 arc-seconds (about 90m) for the rest of the world (for latitudes between
    13    60 degrees North and 54 degrees South).  Starting in 2014, 1 arc-second data is being released for more of the world and as of June 2015 this appears to be available for
    14    everywhere the 3 arc-second data is apart from an area covering Greece, Turkey, the Middle East, and some surrounding countries.  Due to the way the radar mapping was done,
    15    there are some "voids" in this data in areas where the steep terrain shaded the ground from the radar beams.  Even the "void filled" versions still seem to have some voids,
    16    and interesting caves are often in areas of steep terrain.
     12 It was originally released with a resolution of 1 arc-second (about 30m) for the USA and 3 arc-seconds (about 90m) for the rest of the world (for latitudes between
     13 60 degrees North and 54 degrees South).  Starting in 2014, 1 arc-second data is being released for more of the world and as of June 2015 this appears to be available for
     14 everywhere the 3 arc-second data is apart from an area covering Greece, Turkey, the Middle East, and some surrounding countries.  Due to the way the radar mapping was done,
     15 there are some "voids" in this data in areas where the steep terrain shaded the ground from the radar beams.  Even the "void filled" versions still seem to have some voids,
     16 and interesting caves are often in areas of steep terrain.
    1717
    18    You can download SRTM data from various places. I used the [http://earthexplorer.usgs.gov/ USGS Earth Explorer]
    19    which requires registration (which doesn't cost anything) - click on the "Data Sets" tab and look at the "Digital Elevation" section of the tree on the left.  One of the icons
    20    in each entry allows you to see the coverage of each dataset (where it actually has data for).
     18 You can download SRTM data from various places. I used the [http://earthexplorer.usgs.gov/ USGS Earth Explorer]
     19 which requires registration (which doesn't cost anything) - click on the "Data Sets" tab and look at the "Digital Elevation" section of the tree on the left.  One of the icons
     20 in each entry allows you to see the coverage of each dataset (where it actually has data for).
    2121
    2222 * [https://en.wikipedia.org/wiki/Advanced_Spaceborne_Thermal_Emission_and_Reflection_Radiometer Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)] - this
    23    is based on data collected since 2000 by a Japanese sensor on the Terra satellite.  The data resolution is about 30m, and covers latitudes from 83 degrees North to 83 degrees
    24    South (so much better coverage of polar areas than SRTM), but the data seems to be lower quality than SRTM with various artifacts and other problems.
     23 is based on data collected since 2000 by a Japanese sensor on the Terra satellite.  The data resolution is about 30m, and covers latitudes from 83 degrees North to 83 degrees
     24 South (so much better coverage of polar areas than SRTM), but the data seems to be lower quality than SRTM with various artifacts and other problems.
    2525
    26    You can also download this from the [http://earthexplorer.usgs.gov/ USGS Earth Explorer].
     26 You can also download this from the [http://earthexplorer.usgs.gov/ USGS Earth Explorer].
    2727
    2828 * [http://www.viewfinderpanoramas.org/dem3.html Viewfinder Panoramas] has data compiled from various different sources to [http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org3.htm 3 arc-second data globally] and [http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org1.htm 1 arc-second data for the Alps, Tatra, central Spain, and an area covering Scandanavia and part of adjacent countries].
    29    At least for the area around where CUCC visit in Austria this seems to be distinctly better than either SRTM or ASTER.
     29 At least for the area around where CUCC visit in Austria this seems to be distinctly better than either SRTM or ASTER.
    3030
    3131== Formats ==
     
    4242Eventually we'll probably get aven to use GDAL to allow reading terrain data in more formats.  If there are particular formats it would be useful
    4343to be able to read, please [/newticket open a ticket].
     44
     45== Known Issues ==
     46
     47 * #55 Fix terrain rendering to not show terrain through itself
     48 * #56 Sort out handling of geoid
     49 * #57 Smooth shading of terrain
     50 * #53 Texture mapping onto terrain data