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I am using GRASS to extract a specific area from a vector map. Here is the script that I am running:

v.extract PHL_map out=makati where="AREA_NAME = 'Makati"

The problem is, I don't know what are the values of the columnnames. I can only view the columnnames but I cant view the values under the columnnames

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up vote 5 down vote accepted

If you're looking just for column values, you probably want to get back the column values. Just doing map=vector_layer will return a pipe separated list of the attribute table. You can also use columns= to select particular columns, and where= to provide a where clause.

Also useful is db.describe table=vector_layer which will return a list of columns along with their relevant metadata and attributes.

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Thanks. I used: v.extract PHL_adm1 where="NAME_1='Surigao del Sur'" out=surigao but when I loaded the vector layers, the surigao map did not load. This is displayed in the command output: Writing attributes... DBMI-DBF driver error: Unable to create table <angat.surigao> Unable to copy table v.extract complete. (Sat Jan 29 15:23:22 2011) Command finished (0 sec) I don't know why the surigao map did not load.. – teamAngat Jan 29 '11 at 7:30
Note that a dot in a name is not SQL compliant. Please change "angat.surigao" to, for example to "angat_surigao" – markusN Jan 29 '11 at 19:07

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