[GRASS-user] identification of cats of vector areas within current region

[Vincent Bain]

Hello Nikos,

I understand the point is to identify a cat list of features falling
withing the displayed region. In this case, I guess areas whom centroids
are outside the frame won't match... perhaps it would be interesting to
retrieve these values through an intermediate v.overlay (operator=and).
In fact, I don't know how v.overlay behaves with cats, but it may be a
new lead for your purpose!
Good luck,

Vincent



Le dimanche 24 mai 2009 à 14:07 +0200, Nikos Alexandris a écrit :
> Hi list!
> 
> I extract specific areas (g.region vect=sample_map) from a(nother)
> "source_map":
> 
> # display "source" map
> d.vect source display=shape,cat lsize=12
> 
> # zoom in "sample_map" of interest
> g.region vect=sample_2
> 
> ## zoom to ensure seeing all of the features
> # d.zoom, zoom-out/-in, d.redraw, etc.
> # identify cats of interest in the source_map
> 
> ## extract for "region zoomed-in sample_2" the features from source_map
> v.extract source_map out=sample_2_From_source list=35,38 --o
> 
> 
> My question is whether it is possible to automatically identify which
> features (=areas) of a vector map lie within (read: even if their bigest
> part is not within) the "current" region and extract them (as a whole,
> not cut-off the part that is outside of the "region") or... not?!
> 
> Kindest regards, Nikos
> ---
> 
> Hopefully it's clear enough below:
> 
> Data:
> 
> R -> region == some sample
> a, b, c -> features (areas) in the source map
>  _______
> |       |
> | R    |==| |==|
> | |==| |b | |c |
> | |a | |==| |==|
> | |==|  |
> |_______|
> 
> 
> Goal:
> 
> Identify the cats of a, b (NOT c) with *some* command without visually
> inspecting their "cats"?
> 
> or
> 
> Directly extract a and b (NOT c) (with v.extract)?
> 
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