Tips and Tricks
Tips and Tricks
Using QGIS as a frontend to GRASS
QGIS can run as a frontend to GRASS. There is support for displaying maps, editing maps, and execution of simple GIS functions. The GDAL/OGR library is a requirement for that (but for GRASS anyway):
To use the two together, the GDAL-GRASS plugin must be installed:
Test that the GDAL-GRASS plugin is available with this command:
Look for a line like "GRASS (ro): GRASS Database Rasters (5.7+)"
Enable the QGIS GRASS plugin from QGIS:
GUI: Plugins / Plugin Manager / Check the GRASS checkbox
The GRASS toolbar should now be visible. While not a firm requirement, it is easier to start QGIS from within a GRASS session.
Exporting GRASS maps to GMT
GMT (Generic Mapping Tools) is a Free software package for creating publication quality cartography.
GMT homepage: http://gmt.soest.hawaii.edu
Exporting GRASS maps to GMT: http://188.8.131.52/~dylan/grass_user_group/ (Supplied by the GRASS Users Group of Davis, California)
Interfacing R-Statistics with GRASS
R-Statistics homepage: http://www.r-project.org
Using GRASS with an on-line Web-GIS
UMN Mapserver homepage: http://mapserver.gis.umn.edu
Starting and running GRASS from a script
You have to set a couple of variables
export GISBASE=/usr/local/grass60 export PATH=$PATH:$GISBASE/bin:$GISBASE/scripts export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$GISBASE/lib export GISRC=$HOME/.grassrc6 export GRASS_PNGFILE=/tmp/grass6output.png export GRASS_TRUECOLOR=TRUE export GRASS_WIDTH=900 export GRASS_PNG_COMPRESSION=1 export GIS_LOCK=$$ #test: g.version #this should print the GRASS version used.
Then you can launch GRASS commands. This works within Shell scripts and also in the command line terminal.
Running GRASS remotely on OS X
Tiger (OS 10.4) changed the default configuration of SSH from previous versions of OS X. You can no longer start an ssh session with the -X flag and display the Tcl/Tk components of the GRASS GUI remotely. If you are running grass on OS X (10.4) between hosts on a network (i.e. running it on one machine but displaying it on another), you will need to use the "trusted forwarding" mode of SSH in order for the Tcl/Tk generated graphics, such as d.m or gis.m in order for the GUI graphics to make it through your connection. This can be done using the -Y flag when you start the ssh session:
ssh -Y remotehost
Using the -X flag, or simply turning on X11Forwarding in the SSH configuration files, is not enough: the symptoms in this case are that a d.mon window will function fine, but none of the Tcl/Tk dialogues will work, failing with an error message complaining either about Wish not behaving as expected, or a "Bad Atom".