[GRASS-dev] v.external, ogr direct access, topology and pseudo-topology.... a bit confused

[Moritz Lennert]

I don't want to make this discussion go on too long, but

On 20/04/10 13:38, G. Allegri wrote:
> 1 - we had to make a simple points in polygon count. The polygon layer
> wasn't 'clean' (we hadn't perfect boundary adjacency for example), and
> it was made of hundreds of thousands of polygons. The v.in.ogr
> process, and the necessary clean, was taking too much time respect to
> the simple operation we needed, so we imported it in saga, and with a
> few clicks we had our result.

This is typically the example where quick and dirty "works", but where 
it might contain imprecise results if you do not ensure clean polygons: 
any point falling into sliver polygons will be counted double. So this 
is exactly why I would plead for not allowing such operation in GRASS, 
as I see as one of the trademarks and strengths of GRASS its rigour in 
pushing the use as far as possible towards a careful and thoughful use 
of the data.

Moritz