Will any body please suggest any online documentation
(html,pdf etc) to learn GRASS57 database management
and query efficiently.
Ex: I use a vector file with 100 areas involving 10
attributes. How to generate a map with only a couple
of attributes, with a query or something.
Ravi
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On Tuesday 11 January 2005 04:21 am, RAVI KUMAR wrote:
Will any body please suggest any online documentation
(html,pdf etc) to learn GRASS57 database management
and query efficiently.Ex: I use a vector file with 100 areas involving 10
attributes. How to generate a map with only a couple
of attributes, with a query or something.Ravi
you can do this in a couple of ways.
1. display vectors based on their CAT
2. display vectors based on some attribute
3. create a table in the RDBMS of your choice, and use this for deciding which
vectors to display.
I haven't been able to get the db.execute command to work on DBF files, so I
can't help much there. Also the 'where' option in d.vect doesn't seem to do
what I want either (operator error?)...
I have been creating tables in MySQL and using them as a basis for what I want
displayed. For more information on DB stuff, see the GRASS WIKI.
or, I have documented some things on using MySQL here:
http://basho.dept-lawr.ucdavis.edu/grass_and_tp/
cheers!
--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341
> Will any body please suggest any online documentation
> (html,pdf etc) to learn GRASS57 database management
> and query efficiently.
>
> Ex: I use a vector file with 100 areas involving 10
> attributes. How to generate a map with only a couple
> of attributes, with a query or something.
You can extract vector features to new map in GRASS 5.7 with the
v.extract module. see also v.select, v.in.region+v.overlay, etc
you can do this in a couple of ways.
1. display vectors based on their CAT
2. display vectors based on some attribute
3. create a table in the RDBMS of your choice, and use this for
deciding which vectors to display.I haven't been able to get the db.execute command to work on DBF
files, so I can't help much there.
works fine for me. see the v.in.garmin script.
Also the 'where' option in d.vect doesn't seem to do what I want
either (operator error?)...
from:
http://grass.ibiblio.org/grass57/manuals/html57_user/sql.html
Text-string matching requires the text part to be 'single quoted' and
multiple queries should be contained in "double quotes". e.g.
d.vect map where="individual='juvenile' and area='beach'"
Hamish