Geography Reference
In-Depth Information
Figure 12.1: Selecting a GRASS mapset in QGIS
import vector layers using the GRASS toolbox in QGIS. We will now
expand on those concepts by exploring the toolbox in depth, using it
first to load some more data and then to do a bit of data conversion and
analysis. From this point on, we assume a working GRASS install and
a ready-to-use mapset.
12.1
Loading and Viewing Data
If you work through the GRASS basics in Appendix C , on page 296 , you
end up with two vector layers in your mapset: cities and world_borders .
Our goal now is to add the world mosaic to GRASS using the toolbox.
To do this, we first add world_mosaic.tif to QGIS as a regular raster layer.
Once it's loaded up, we need to open our mapset using the Open mapset
menu item in the GRASS menu (remember the GRASS menu is located
under the Plugins main menu). The mapset we want is in our world_lat_lon
location. In Figure 12.1 , you can see the dialog box used to open a
mapset in QGIS. Notice that you can open any mapset in any location in
any GRASS database using this dialog box. As you change the Gisdbase
location, either by typing a path or by browsing to it, the Location and
Mapset drop-downs change to reflect what's available.
Once we open the mapset, the Open GRASS tools tool becomes active on
the GRASS toolbar, as do the region and vector edit tools. Now that the
mapset is open, we can open the GRASS toolbox. Click the Open GRASS
Tools tool and wait as the toolbox initializes. The tools in the toolbox
are added dynamically. In fact, you can customize the tools and add
more GRASS functionality. The downside (well sort of) is that the more
tools in the box, the longer it takes to open. Once it's up and initialized,
 
 
 
 
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