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

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 paste below a SS of my current POINT data

<http://osgeo-org.1560.x6.nabble.com/file/n5200420/Pts_TC.jpg&gt;

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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