[GRASS-user] v.overlay: An Observation About Time

[MS]

v.select can be a nice first pass to filter back a substantial amount  
of unnecessary data.

Mark

On Dec 30, 2009, at 2:33 PM, Rich Shepard <rshepard at appl-ecosys.com>  
wrote:

>  I have a map of water bodies for the entire state. Yesterday, when I
> re-imported it (correctly), it took about 3 hours to complete; most  
> of the
> time was waiting for it to 'break boundaries'.
>
>  Today I'm clipping it to a very small region, one drainage basin  
> and parts
> of the surrounding basins, yet it's taking about the same amount of  
> time.
> Yes, there are a lot of nodes, vertices, and primitives, but I want  
> only
> those within the area of the overlaid map. So I'm surprised it's  
> taking as
> long as it is.
>
>  This is an extensive original map:
>
> Building topology for vector map <bl_lakes>...
> Registering primitives...
> 220819 primitives registered
> 4589198 vertices registered
> Number of nodes: 158848
> Number of primitives: 220819
> Number of points: 0
> Number of lines: 0
> Number of boundaries: 220819
> Number of centroids: 0
> Number of areas: -
> Number of isles: -
> Breaking lines...
> Removing duplicates...
> Cleaning boundaries at nodes...
> Breaking lines...
>
>  This is not a complaint, but an observation.
>
> Rich
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