Changes between Version 10 and Version 11 of Help/DEM_scripts


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Timestamp:
Feb 11, 2012 2:03:16 PM (8 years ago)
Author:
adbe
Comment:

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  • Help/DEM_scripts

    v10 v11  
    5555    *  Select the purpose of the tile usage
    5656    *  Then download the tiles.
    57 
     57The files that are used for the elevation model are called ASTGTM*_dem.tif
    5858==== Choosing Tiles ====
    5959When creating an ASTER DEM it is important to choose the correct tiles to use, as this could impact on the speed at which the script runs, as if tiles with large gaps between them are chosen when grass fills the nulls it has a lot of nulls to fill, so will take a very long time.
     
    6161If you require tiles in the region (50.23 - 52.56, -2.34 - 1.23) lat/lon:
    6262  To calculate the tiles round the numbers down to get (50 - 52, -3 - 1), so you need:
    63      ASTGTM2_N50W003_dem.tif
    64      ASTGTM2_N50W002_dem.tif
    65      ASTGTM2_N50W001_dem.tif
    66      ASTGTM2_N50E000_dem.tif
    67      ASTGTM2_N50E001_dem.tif
    68      ASTGTM2_N51W003_dem.tif
    69      ASTGTM2_N51W002_dem.tif
    70      ASTGTM2_N51W001_dem.tif
    71      ASTGTM2_N51E000_dem.tif
    72      ASTGTM2_N51E001_dem.tif
    73      ASTGTM2_N52W003_dem.tif
    74      ASTGTM2_N52W002_dem.tif
    75      ASTGTM2_N52W001_dem.tif
    76      ASTGTM2_N52E000_dem.tif
    77      ASTGTM2_N52E001_dem.tif
     63     ASTGTM2_N50W003_dem.tif[[BR]]
     64     ASTGTM2_N50W002_dem.tif[[BR]]
     65     ASTGTM2_N50W001_dem.tif[[BR]]
     66     ASTGTM2_N50E000_dem.tif[[BR]]
     67     ASTGTM2_N50E001_dem.tif[[BR]]
     68     ASTGTM2_N51W003_dem.tif[[BR]]
     69     ASTGTM2_N51W002_dem.tif[[BR]]
     70     ASTGTM2_N51W001_dem.tif[[BR]]
     71     ASTGTM2_N51E000_dem.tif[[BR]]
     72     ASTGTM2_N51E001_dem.tif[[BR]]
     73     ASTGTM2_N52W003_dem.tif[[BR]]
     74     ASTGTM2_N52W002_dem.tif[[BR]]
     75     ASTGTM2_N52W001_dem.tif[[BR]]
     76     ASTGTM2_N52E000_dem.tif[[BR]]
     77     ASTGTM2_N52E001_dem.tif[[BR]]
    7878  The name of the tiles relates to the bottom left corner of the region so ASTGTM2_N50W003_dem.tif covers (50-50.9999, 3-3.0001).
    7979
     
    167167      -a:   Directory containing ASTER tiles only. If not given then script needs to be run within a project[[BR]]
    168168      -g:   Grass database to use, defaults to creating one[[BR]]
    169       -p:   Projection of output tiles:proj4 string or UTM[utm_num(zero padded)](N|S) or UKBNG or ll[[BR]]
     169      -p:   Projection of output tiles: proj4 string or UTM[utm_num(zero padded)](N|S) or UKBNG or ll[[BR]]
    170170      -r:   Resolution of output DEM, defaults to using resolution of ASTER tile[[BR]]
    171171      -s:   binary geoid-spheroid seperation file[[BR]]
     
    173173      -f:   Do not fill nulls or smooth, i.e. do not run the command r.fillnulls and r.neighbours on the DEM before outputting[[BR]]
    174174
    175 
     175Examples:
     176  *  Create an ASTER DEM from tiles in the directory aster_tiles and create an output file called a_dem_filename.dem:
     177     *  {{{asterdem.sh -a aster_tiles/ -o a_dem_filename.dem}}}
     178  *  Create an ASTER DEM jpg image from tiles in a directory:
     179     *  {{{asterdem.sh -a aster_tiles/ -j a_dem_filename.jpg}}}
     180  *  Project some ASTER tiles to a UKBNG projection and output the DEM to a_dem_filename.dem (Separation file uk_separation_file_WGS84LL.dem is used automatically):
     181     *  {{{asterdem.sh -a aster_tiles/ -p UKBNG -o a_dem_filename.dem}}}
     182  *  Project some ASTER tiles to a utm30n projection and output the DEM to a_dem_filename.dem:
     183     *  {{{asterdem.sh -a aster_tiles/ -p UTM30N -o a_dem_filename.dem}}}
     184  *  Project some ASTER tiles to a proj4 string projection:
     185     *  {{{asterdem.sh -a aster_tiles/ -p "+proj=utm +zone=30 +ellps=WGS84 +datum=WGS84" -o a_dem_filename.dem}}}
     186  *  Project some ASTER tiles to a proj4 projection using a separation file of your own making:
     187     *  {{{asterdem.sh -a aster_tiles/ -p "+proj=utm +zone=30 +ellps=WGS84 +datum=WGS84" -o a_dem_filename.dem -s my_separation_file.dem}}}
     188  *  Create an ASTER DEM in and leave it in a grass database and do not fill nulls or smooth the DEM:
     189     *  {{{asterdem.sh -a aster_tiles/ -f}}}
    176190
    177191