Re: [GRASS-user] Connecting table

[Micha Silver]

On 01/03/2012 10:44 PM, Bulent Arikan wrote: Thank you! This seems to be an interesting solution to the problem especially because it involves changing the driver from DBF to SQLITE. I ended up using 'v.rast.stats', which adds columns for extended statistics and uploads values all at once. The only thing is: data are recorded as part of the same layer (i.e., Layer 1). So, I cheated! Yes, v.rast.stats is definitely the way to go if you want raster univariate statistics pushed into a polygon vector. However, I started trying your method. I created a new mapset to use sqlite and copied some vector maps from a mapset where default driver is DBF. I defined SQLITE as the new driver in the new mapset using 'db.connect'  (driver=sqlite, database='$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite.db', no flags checked). Then I wanted to use 'v.db.connect' for a vector map but I cannot select table name etc. I also tried just using 'v.db.connect' but I still cannot see anything under Table. So. I am confused about how to define a new driver in a mapset. I do as follows: eval `g.gisenv` (This creates the environment variables for GISDBASE, etc.) Now: db.connect driv=sqlite database=$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite.db Next: g.copy vect=old,new to create a new copy of the original vector. The original will still have its attrib table as dbf. THe new copy will have an sqlite based attribute table. Now you can do: v.db.addcol <new_vector> col="..., ..." . BTW, I think that v.rast.stats will automatically create the needed columns . Cheers, Micha Thank you again, Bulent On Tue, Jan 3, 2012 at 9:13 PM, Micha Silver <mi...@arava.co.il> wrote: On 01/03/2012 04:50 PM, Bulent Arikan wrote: Dear List, I rasterized a centroid and ran 'r.univar', whose extended stats are saved as a text file. Then, I ran 'v.db.addtable' to create a second layer in the attribute table of the centroid and I had columns added in this second layer using 'v.db.addcol'. I want GRASS to upload values from the text file but I am not sure how to perform this task.  Is there a shorter way of creating a second layer and uploading values from the text file or what should I do next so that the columns in the second layer will be populated using the text file I have? I'm not sure about a shorter way, but here's an option: First setup your mapset to save attributes to sqlite. > v.db.connect centroid driver=sqlite database=.... Now add the columns which will accept r.univar values to the sqlite table: > v.db.addcol centroid col="n double, null_cells double, cells double, min double, max double, range double, mean double, mean_of_abs double, stddev double, variance double, coeff_var double, sum double" Run r.univar on your raster, putting results into a text file > r.univar your_rast -g  > univar.txt Now do this loop to update values for the centroid: > while read l; do \     col=`echo $l | cut -d= -f1`; val=`echo $l | cut -d= -f2`; \     sqlite3 sqlite.db "UPDATE centroid SET ${col}=${val} ;"; \ > done < univar.txt Assuming you want to run this for several centroids/areas, you'll probably want to add a WHERE clause to the UPDATE statement so as to put values for only one certain row (centroid). HTH, Micha Thank you for your time. GRASS 6.5 svn on Snow Leopard -- BÜLENT This mail was received via Mail-SeCure System. _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user This mail was received via Mail-SeCure System. -- Micha Silver GIS Consultant, Arava Development Co. http://www.surfaces.co.il -- BÜLENT ARIKAN, PhD Senior Research Fellow Research Center for Anatolian Civilizations Koç University İstiklal Caddesi No: 181 Merkez Han Beyoğlu - ISTANBUL TURKEY 34433 (+ 90) 212-393-6036 This mail was received via Mail-SeCure System.

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