[GRASS-user] Re: Problem with creating layer 2 data

GRASS GRASS user
1

As a followup, when I created the second layer I used

v.db.connect map=baseMap driver=sqlite table=CountyData key=FIPS layer=2

There is a column in baseMap called FIPS but it is not the category data. Is the link with the attribute table from layer 1 automatic? Do I need to create a cat field in CountyData? If I do, how to I link it with the FIPS column in baseMap?

Because of the possibility that there are multiple vector regions for a county in baseMap, there are many cases of repeated values for the FIPS data, but they are unique in CountyData.

Could another possibility be in how I imported the data into SQLite? I used a straight forward db.copy of a DBF file.

This is Grass 6.3 on OS X. I read that there was a problem with labeling on layer 1 with 6.2, but is the same type problem?

2

On Fri, May 23, 2008 22:28, J. Brian Adams wrote:

As a followup, when I created the second layer I used

v.db.connect map=baseMap driver=sqlite table=CountyData key=FIPS
layer=2

This does not create a second layer, it connects a table to the second
layer. To create a second layer you need to use v.category.

See also
http://grass.osgeo.org/wiki/Vector_Database_Management#Concepts_and_jargon

We could really use some more extended documentation about layer
management...and some more tools, such as the possibility to apply the
cats of one layer to another. See
http://lists.osgeo.org/pipermail/grass-user/2008-March/044181.html (point
3) for a work-around.

Moritz