Difference between revisions of "GRASS 6 Tutorial/Raster data management"

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(Created page with "==Raster data management== ===Overview=== This section of the tutorial is intended to provide new users with an introduction to raster data management in GRASS GIS. As with o...")
 
 
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==Raster data management==
 
==Raster data management==
===Overview===
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===Data Import===
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In a similar way to the vector data management, the import and export of raster data is underpinned by GDAL. As such, the modules, <code>r.in.*</code> and <code>r.out.*</code> and specifically, <code>r.in.gdal</code> and <code>r.out.gdal</code> are used. The module <code>r.extenal</code> can be used in lieu of importing a raster into GRASS.
  
This section of the tutorial is intended to provide new users with an introduction to raster data management in GRASS GIS. As with other parts of the GRASS 6 tutorial, the examples are largely based on the GRASS 5.7 tutorial as well as the GRASS GIS presentation at Geostat-2012.  
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A Geotiff can be imported into GRASS using the command line (input represents the full or relative path to the raster file you want to import;  output is its raster name in GRASS). The same can be achieved using the GUI.  
  
In a similar way to the vector data management, the import and export of raster data is underpinned by GDAL. As such, the modules
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r.in.gdal input=elev_input_state500m.tif output=elev_input_state500m
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[[File:Grass raster import.png|400px]]
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Sometimes, you need to define the region of the Mapset to the extent of your raster. For instance, using the above-mentioned example, you would simply:
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g.region rast=elev_input_state500m
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A common issue that users are faced with is how to import several GeoTiffs? Obviously the above steps can be repeated using the GUI or copy-pasting the command line or more simply using the following BASH for loop:
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for file in `ls *.tif`
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  do
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  r.in.gdal input=$file output=${file%.tif}
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done
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''Note - that when you run r.in.gdal, the full extent of the map is imported''
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[[Category: Tutorial]]

Latest revision as of 01:47, 9 August 2013

Raster data management

Data Import

In a similar way to the vector data management, the import and export of raster data is underpinned by GDAL. As such, the modules, r.in.* and r.out.* and specifically, r.in.gdal and r.out.gdal are used. The module r.extenal can be used in lieu of importing a raster into GRASS.

A Geotiff can be imported into GRASS using the command line (input represents the full or relative path to the raster file you want to import; output is its raster name in GRASS). The same can be achieved using the GUI.

r.in.gdal input=elev_input_state500m.tif output=elev_input_state500m

Grass raster import.png


Sometimes, you need to define the region of the Mapset to the extent of your raster. For instance, using the above-mentioned example, you would simply:

g.region rast=elev_input_state500m

A common issue that users are faced with is how to import several GeoTiffs? Obviously the above steps can be repeated using the GUI or copy-pasting the command line or more simply using the following BASH for loop:

for file in `ls *.tif`
 do
  r.in.gdal input=$file output=${file%.tif}
done


Note - that when you run r.in.gdal, the full extent of the map is imported