Changes between Version 4 and Version 5 of Help/DEM_scripts

Timestamp:

Feb 9, 2012, 2:26:47 PM (13 years ago)

Author:

adbe

Comment:

--

Help/DEM_scripts

@@ -11 +11 @@
 === GRASS GIS ===
 GRASS is a GIS (Geograohic Information System) and details of it can be found at: http://grass.fbk.eu/. There is a detailed api and usage guide, it is available for free download at: http://grass.fbk.eu/download/index.php, as the scripts are written to run on linux, depending on your build of fedora run the following to install grass, the scripts use grass63 by default:
-  *  {{{sudo yum install grass}}}
-  *  {{{sudo apt-get install grass}}}
-To get started download the template grass database: [attachment:grass_db_template]
+
+To get started download the template grass database: [attachment:grass_db_template.zip]
+  *  Run the command: {{{unzip grass_db_template.zip}}}
+  *  To check that the grass download works run: grass63 -text grass_db_template/UKBNG/PERMANENT/
+    *  If it did not work successfully check the grass version that you have and the path to the grass template database
+    *  If it did work successfully press Ctrl-D or type exit to exit
 
 === Creating a DEM from ASTER data using ''asterdem.sh'' script ===
@@ -64 +67 @@
   *  http://www.ordnancesurvey.co.uk/oswebsite/gps/docs/OSTN02_OSGM02files.zip
   *  Once the file has been downloaded run the command: {{{mkdir OSTN02_OSGM02files; unzip OSTN02_OSGM02files.zip -d OSTN02_OSGM02files}}}
-  *  
+  *  Now run: {{{grass63 -text /PATH/TO/grass_db_template/UKBNG/PERMANENT/}}}
+  *  Grass should have opened if it did not look at the section above on Grass GIS
+  *  First get the region that is going to be read in:
+     *  {{{r.in.xyz input=OSTN02_OSGM02_GB.txt output=OSTN02_OSGM02_GB.txt x=2 y=1 z=6 fs="," --overwrite -s}}}
+        *  This should return:
+            ||Range:||min       ||max          ||
+            ||x:    ||0.000000  ||700000.000000||
+            ||y:    ||1.000000  ||876951.000000||
+            ||z:    ||-81.603000||0.000000     ||
+     *  Then actually set the region based on this, include a buffer size of 1 metre, resolution is 1000 for this file: 
+        {{{g.region e=700001 w=-1 n=876952 s=0 res=1000}}}
+     *  Now read in the separation file: 
+        {{{r.in.xyz input=OSTN02_OSGM02_GB.txt output=OSTN02_OSGM02_GB.txt x=2 y=1 z=6 fs="," --overwrite}}}
+     *  Now to check that the reading in of the file has worked run: 
+        {{{gis.m}}}
+        *  In the manager click on "Add raster layer"
+        *  Then click on "Base map" and select "OSTN02_OSGM02_GB.txt"
+        *  In the "Map Display" click on "Redraw all layers". 
+        *  You should now see the raster map that has been read in
+     *  Now the separation file has been read in a separation DEM can be created
+        *  The raster map can be output to a file with the following command: 
+           {{{r.out.gdal input=OSTN02_OSGM02_GB.txt output=uk_separation_file_UKBNG.dem format=ENVI type=Float32 nodata=0 --overwrite}}}[[BR]]
+           {{{rm -f uk_separation_file_UKBNG.dem.aux.xml}}}
+        *  This DEM can be used as a separation file when projecting from osgb36 UKBNG to wgs84 lat/lon, however, we want it for projecting the other way. The DEM we have created here can be used later for use with the LiDAR, so do not remove it.
+     *  To project the DEM:
+        *  First we need to get a vector representing the entire region of the DEM:
+           {{{v.in.region output=total_reg type=area --overwrite}}}
+        *  Then to get the resolution projected:
+           *  Save the so that we can get back here
+              {{{g.region save=actualregion --overwrite}}}
+           *  Set the region to the the bottom left corner based on the resolution:
+              {{{g.region n=s+`echo \`g.region -p | grep nsres\` | awk '{print $2}'` e=w+`echo \`g.region -p | grep ewres\` | awk '{print $2}'`}}}
+           *  Create a vector box based on the resolution:
+              {{{v.in.region output=vector_box_res type=area --overwrite}}}
+           *  Reset the region:
+              {{{g.region actualregion}}}
+        *  
+           
+
+
+
+
+
+
+
+
+