[GRASS-user] [GRASSLIST:1148] Attribute editing

[Joel Pitt]

On 7/7/06, Maciek Sieczka <werchowyna at epf.pl> wrote:
> You can't edit a category number. You can only edit attributes (besides
> the key column, usually and by default called "cat"). Category is a
> unique vector feature ID - if you could edit it, you would loose
> connection between the vactor feature and it's attributes in table.
> Read: http://grass.itc.it/grass61/manuals/html61_user/vectorintro.html

You can edit categories with v.category can't you?

Although it seems that only systematic changes, such as adding a value
to all categories, or generating a new category index.

Does anyone know if all vector objects MUST have a unique category?
I have a shape file of US counties, and want to link it to a table of
county information which have the FIPS code as a key. However, because
counties are not all singular vector objects some have more than one
category.

I could link the county information directly to the category numbers.
But this would end having lots of duplicate entries where the FIPS
code of entries is the same but with different category numbers.

Ideally I'd like to be able to use the FIPS code as the category
number - but if category number must unique then I have to go with
duplicate entries.

Thanks,

-- 
-Joel

"Wish not to seem, but to be, the best."
                -- Aeschylus