[GRASSLIST:4184] Re: Adding CATs back to output from v.buffer/v.distance in 5.7 on Linux - Redhat

[Radim Blazek]

On Saturday 14 August 2004 01:32, Craig Aumann wrote:
> GRASS 5.7.0:~/grassalpac > v.category in=wellsselect field=1
> option=print
> 9202
> 42724
> 57869
> 58276
> 62189
> 65873
> 67256
>
> GRASS 5.7.0:~/grassalpac > v.buffer input=wellsselect output=wellstemp
> type=point buffer=100

> Number of nodes     :   12
> Number of primitives:   12
> Number of points    :   0
> Number of lines     :   0
> Number of boundaries:   6
> Number of centroids :   6
> Number of areas     :   6
> Number of isles     :   6
> GRASS 5.7.0:~/grassalpac >
>
> ---------------------------------------------------
> DON'T UNDERSTAND WHY THERE ARE ONLY 6 AREAS - THE ORIGINAL POINTS
> ARE DISTINCT AND DO NOT OVERLAP - EVEN WITH MUCH LARGER BUFFERS THAN I
> AM USING.
> ---------------------------------------------------

It could be a bug, but are you sure that 42724 and 57869 have 
distinct coordinates? Can you send here an output of
'v.out.ascii input=wellsselect'?

> NOW, WHAT IS THE v.category COMMAND THAT I NEED TO ISSUE TO GET LINK_KEY
> FROM THE LINKED TABLE COPIED OVER INTO THE CAT FOR A GIVEN FIELD (1 OR
> 3).  I JUST CAN'T FIGURE THIS OUT.  ALL THE OPTIONS I TRY DON'T HAVE THE
> DESIRED BEHAVIOR.

v.reclass input=wellsbuf output=wellsbufcat col=link_key

What you have done is correct, another way to do that is to extract 
only boundary from 'wellstemp' (v.extract), convert points in 'wellsselect' 
to centroids (v.type) and patch them together (v.patch). Unfortunately
v.extract does not work with type only, so cats must be assigned to boundaries 
first (v.category).

Note: this feature is already on TODO list for v.buffer.

Radim