[GRASS5] more cats in one layer and where condition

[Martin Landa]

Hi,

On Thu, 05 May 2005, Radim Blazek wrote:

> >>>the problem which I described in last e-mail (d.vect disp=cat|attr
> >>>where=) is more complex (as I have found out using ps.map)...
> >>
> >>does v.extract work or does it have the same problem?
> >
> >
> >it seems that v.extract works correctly...
> >
> >btw, I am trying to add multiple layer support to this module.
> >
> >	v.extract ... [layer=value[,value,...]] ...
> >
> >It is almost done.
> 
> How should it work? Currently the layer option is used together with 
> (list or where) and type. How do you want to use more layers?
> 

you are right, I am not sure how to implement it (with where, list, type option)
in the right way...

The reason why I have modified this module:

I have a map which contains more thematic layers (e.g. parcels and buildings).
I need to split this map into two maps.

v.extract in=map out=map_parcels layer=1,2,3,4,5,.... 
v.extract in=map out=map_buildings layer=50,51,52,....

I am not sure how to do it in one step. Of course I can use v.extract
more times, then patch these maps and clean the result. But it takes
a lot of time and I think it is not a good way...

So, do you know how to solve this problem without modifying v.extract?

Thanks,

	Martin

--
Martin Landa <landa at gama.fsv.cvut.cz> * http://gama.fsv.cvut.cz/~landa *
CTU Prague, Faculty of Civil Engineering, Czech Republic