[GRASS-user] RST - how does it chooses from near points?

[Carlos "Guâno" Grohmann]

This is Helena's answer:

> Carlos,
>
>  first point found at a given location is preserved and any consequent
> points within distance smaller than dmin are ignored (the z-values are
> not taken into account). I have done some experiments with 3D distance as
> well if you need to take into account the z - it is very easy to change
> that in the code but that would require adding a flag and I am not sure
> that many users would need it.
> If your data are contours, use v.generalize to "thin" the points first -
> it speeds up the processing a lot and the results are much better - see
> here:
> http://skagit.meas.ncsu.edu/~helena/grasswork/interpgen.html
> If you want to use mean value of your close points - the best approach is
> through r.in.xyz - see the example in its man page
>
> Helena


cheers




On Wed, May 28, 2008 at 5:19 AM, Markus Neteler <neteler at osgeo.org> wrote:
> Maybe best ask to Helena who is on the road and not subscribed
> to this list AFAIK...
> please post the answer then!
>
> markus
>
> On Tue, May 27, 2008 at 9:39 PM, Carlos Guâno Grohmann
> <carlos.grohmann at gmail.com> wrote:
>> It just came to me: if I have a vector map to be interpolated by RST,
>> how does the algorithm chooses between points that are very close to
>> each other?
>> And if I have more than one point with the same coordinates, but
>> different values?
>>
>> thks all
>>
>> Carlos
>>
>> --
>> +-----------------------------------------------------------+
>>  Carlos Henrique Grohmann - Guano
>>  Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
>> Linux User #89721 - carlos dot grohmann at gmail dot com
>> +-----------------------------------------------------------+
>> _________________
>> "Good morning, doctors. I have taken the liberty of removing Windows
>> 95 from my hard drive."
>> --The winning entry in a "What were HAL's first words" contest judged
>> by 2001: A SPACE ODYSSEY creator Arthur C. Clarke
>>
>> Can't stop the signal.
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>
>
>
> --
> Open Source Geospatial Foundation
> http://www.osgeo.org/
> http://www.grassbook.org/
>



-- 
+-----------------------------------------------------------+
 Carlos Henrique Grohmann - Guano
 Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
_________________
"Good morning, doctors. I have taken the liberty of removing Windows
95 from my hard drive."
--The winning entry in a "What were HAL's first words" contest judged
by 2001: A SPACE ODYSSEY creator Arthur C. Clarke

Can't stop the signal.