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<TITLE>New thematic mapper for GRASS 6</TITLE>
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<FONT FACE="Skia, Verdana, Helvetica, Arial"><SPAN DEFANGED_STYLE='font-size:12.0px'>I’ve just finished a thematic mapper for vector maps in GRASS 6, d.vect.thematic, and am hoping that some of you can help test it. It’s done as a shell script (actually 2 scripts). These can be dropped into the $GISBASE/scripts folder.<BR>
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D.vect.thematic will create thematic vector maps of graduated colors or graduated point sizes by regular intervals, standard deviation units, or quartiles. It creates a legend of sorts in the output area of the GUI dialog, that can be cut and pasted into another application. Currently it only works for numeric fields in the connected attribute table, like d.vect.chart. However, I hope that this still will be helpful to GRASS users and respond to the criticism that GRASS lacks thematic mapping.<BR>
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To do this, I had to create a script-based stats program, v.univar.sh, that is based on r.univar.sh. Markus has suggested that it would be much faster if I could use the C-code v.univar module. I’d be happy to, but it needs to be updated somewhat. I need to be able to get the mean and standard deviation for all vector types, not just points. I’m not sure why that limitation is there—maybe a legacy of s.univar. I also need to get quartiles. If someone can do this, I can modify d.vect.thematic to use v.univar instead of v.univar.sh.<BR>
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The same thing goes for r.univar. It would be pretty easy to create a d.rast.thematic using an updated r.univar (with quartiles).<BR>
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Also, maybe someone can come up with a way to make a nicer legend for d.vect.thematic. It would be great to have actual colors (as points, lines, and areas) or point icons showing rather than just the R:G:B code or point size (as I’ve done here). Maybe someone with a bit more tcltk skills could do this.<BR>
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Let me know what you think. If it seems to work for everyone, I’ll go ahead and add it to the CVS and the GIS Manager menus.<BR>
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Michael<BR>
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____________________<BR>
C. Michael Barton, Professor of Anthropology<BR>
School of Human Evolution and Social Change<BR>
PO Box 872402<BR>
Arizona State University<BR>
Tempe, AZ 85287-2402<BR>
USA<BR>
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Phone: 480-965-6262<BR>
Fax: 480-965-7671<BR>
www: <www.public.asu.edu/~cmbarton><BR>
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