I'd be grateful if someone could advise on the appropriate use of v.to.rast
on points vector data. The issue is in selecting the maximum resolution
that still correctly converts all the points, without losing any because
two or more points end up in the same raster grid cell. At the moment we
are using a trial and error approach, by rasterising the points, then
running r.stats to count the number of pixels. I recall the old s.to.rast
flagging a warning if the resolution was incorrect on rasterisation, but
can't work out how to enable this in GRASS 6.2.
Many thanks
Roy
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Roy Sanderson
Institute for Research on Environment and Sustainability
Devonshire Building
University of Newcastle
Newcastle upon Tyne
NE1 7RU
United Kingdom
I believe you have to find out what is the shortest distance between
two of your points. Then set the resolution to half of that value.
Not sure how to do that in Grass but that's the idea.
Cheers
Daniel
On 5/25/07, Roy Sanderson <R.A.Sanderson@newcastle.ac.uk> wrote:
Hello
I'd be grateful if someone could advise on the appropriate use of v.to.rast
on points vector data. The issue is in selecting the maximum resolution
that still correctly converts all the points, without losing any because
two or more points end up in the same raster grid cell. At the moment we
are using a trial and error approach, by rasterising the points, then
running r.stats to count the number of pixels. I recall the old s.to.rast
flagging a warning if the resolution was incorrect on rasterisation, but
can't work out how to enable this in GRASS 6.2.
Many thanks
Roy
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-------
Roy Sanderson
Institute for Research on Environment and Sustainability
Devonshire Building
University of Newcastle
Newcastle upon Tyne
NE1 7RU
United Kingdom
Roy Sanderson wrote:
> I'd be grateful if someone could advise on the appropriate use of
> v.to.rast on points vector data. The issue is in selecting the
> maximum resolution that still correctly converts all the points,
> without losing any because two or more points end up in the same
> raster grid cell. At the moment we are using a trial and error
> approach, by rasterising the points, then running r.stats to count
> the number of pixels. I recall the old s.to.rast flagging a warning
> if the resolution was incorrect on rasterisation, but can't work out
> how to enable this in GRASS 6.2.
Daniel Victoria wrote:
I believe you have to find out what is the shortest distance between
two of your points. Then set the resolution to half of that value.
Not sure how to do that in Grass but that's the idea.