Creating a new GRASS LOCATION

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2009年8月18日 (火) 14:16時点におけるKayama (トーク | 投稿記録)による版

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Creating a new GRASS LOCATION

As an an example you find the instructions how the sample GRASS LOCATION alaska, which is projected in Albers Equal Area projection with unit feet was created for the QGIS sample dataset. This sample GRASS LOCATION alaska will be used for all examples and exercises in the following GRASS GIS related chapters. It is useful to download and install the dataset on your computer #label_sampledata">>). <P>

<A NAME="fig:create_grass_location"></A><A NAME="107"></A>
Figure: Creating a new GRASS LOCATION or a new MAPSET in QGIS

[clip=true, width=10cm]create_grass_location

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  1. Start QGIS and make sure the GRASS plugin is loaded
  2. Visualize the alaska.shp Shapefile (see Section #sec:load_shapefile) from the QGIS alaska dataset #label_sampledata.
  3. In the GRASS toolbar, click on the grass_open_mapsetOpen mapset icon to bring up the MAPSET wizard.
  4. Select an existing GRASS database (GISDBASE) folder grassdata or create one for the new LOCATION using a file manager on your computer. Then click Next.
  5. We can use this wizard to create a new MAPSET within an existing LOCATION (see Section 9.3.2) or to create a new LOCATION altogether. Click on the radio button Create new location (see Figure 28).
  6. Enter a name for the LOCATION - we used alaska and click Next
  7. Define the projection by clicking on the radio button Projection to enable the projection list
  8. We are using Albers Equal Area Alaska (feet) projection. Since we happen to know that it is represented by the EPSG ID 2964, we enter it in the search box. (Note: If you want to repeat this process for another LOCATION and projection and haven't memorized the EPSG ID, click on the mIconProjectionEnabledprojector icon in the lower right-hand corner of the status bar (see Section #label_projstart).
  9. Click Find to select the projection
  10. Click Next
  11. To define the default region, we have to enter the LOCATION bounds in north, south, east, and west direction. Here we simply click on the button Set current QGIS extent, to apply the extend of the loaded layer alaska.shp as the GRASS default region extend.
  12. Click Next
  13. We also need to define a MAPSET within our new LOCATION. You can name it whatever you like - we used demo. footnode.html#foot487
  14. Check out the summary to make sure it's correct and click Finish
  15. The new LOCATION alaska and two MAPSETs demo and PERMANENT are created. The currently opened working set is MAPSET demo, as you defined.
  16. Notice that some of the tools in the GRASS toolbar that were disabled are now enabled.

<P> If that seemed like a lot of steps, it's really not all that bad and a very quick way to create a LOCATION. The LOCATION alaska is now ready for data import (see Section 9.4). You can also use the already existing vector and raster data in the sample GRASS LOCATION alaska included in the QGIS alaska dataset #label_sampledata and move on to Section 9.5.

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