[GRASS-user] How to convert points distribution toward surface information?

[Moritz Lennert]

On 08/04/15 15:38, image93 wrote:
> Good afternoon,
>
>
> I have a points cover representing different bus and train stops. I applied
> a categorized symbology : Each colour represents a class of value (field
> regarding time acess from a starting point)
>
> Iwould like represents this time information thanks to different polygons,
> (Because in a 2nd time i have to intersects this information with another
> POINTS cover )
>
> Could you throw light for me? Rasterize this data would be a interesting
> way? I tried with qgis vector -> convex envelope . But The result is not
> what I am looking for ... the spatial distribution of points seems to be to
> complex to convert the points cover toward convex envelope.


I'm not sure if I really understand what you are aiming at, but here's 
some (possibly useful) paths:

- use v.distance to identify for each point in point map 2 the closest 
point in point map 1

- if you really want polygons, try v.voronoi on point map 1 (= nearest 
neighbor interpolation)

- interpolate your point map 1 to a raster map (v.surf.rst, v.surf.idw, 
r.grow.distance ...)

Moritz