[GRASS-user] populating dbtable with value sequence

Shaun Langley shaunlangley at gmail.com
Thu Apr 18 06:52:12 PDT 2013

**This question is also posted on stackexchange.com**

I have a vector map that includes 100 points. These points were created using v.extract to randomly sample a larger map of 10k points. As such, the 'cat' values range from 1 to more than 10k. What I would like to do is to update the attribute table by rescaling these values to 1 to 100.

Here's what I've experienced. If I use

v.category input=pts100 output=foo option=del
v.category input=foo output=pts100 option=add --o
Then when the 'cat' values appear rescaled when I print them with

v.category input=pts100 option=print
However, if I look at the dbtable with

db.select pts100
the 'cat' values have not changed (presumably because it is the key column).

So I'm thinking I will need to add a new column using v.db.addcol, but I don't know how to specify the range of value to populate the new column. From what I can tell, I have to specify a single value.

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