[GRASS-user] how to calculate area of voronoi polygons considering the boundary of the catchment

[daljeet]

http://www.intevation.de/rt/webrt?serial_num=4292&display=History

The problem that we are facing may be related to above issue.

Thanks
Daljeet 
 

daljeet wrote:
> 
> These white spots in the voronoi vector may be the cause. But i ran the
> voronoi module on the "archsites" vector of the Spearfish60 dataset and
> its runs fine. The cmd was
> 
> v.voronoi input="archsites" output="arch_voronoi"
> 
> The only difference is that the region of archsites has got less points 
> (around 25) whereas in Ind_rain_orig the total points were 93,000. Can
> this be an issue. Can you test the module at your end with less and huge
> data points and see if you also get similar results in both the cases.
> This would be a great help. 
> 
> Also, i checked and the data of rain fall on voronoi vector is NOT NULL on
> these white spots (checked using v.what.vect).
> 
> //d.vect Ind_rain_orig
> //The  Ind_rain_orig looks like this - when the region is set to vector of
> Kerala
> //g.region vect=ker_rain_v
> 
>  http://n2.nabble.com/file/n3345107/Ind_rain_orig_reg_ker.png 
> 
> But when the region is set to Ind_adm2_v (whole  country) the image is
> like 
> //g.region vect=Ind_adm2_v
> //d.vect Ind_rain_orig
> 
>  http://n2.nabble.com/file/n3345107/Ind_rain_orig_reg_adm2.png 
> 
> Thanks
> Daljeet
> 
> Moritz Lennert wrote:
>> 
>> On 28/07/09 18:42, daljeet wrote:
>>> Hi Moritz,
>>> 
>>> I am new to GRASS and the basic concepts of this field. Below, I tried
>>> my
>>> best to share all the information. Please write if I have missed
>>> anything.
>> 
>> This is perfect, thanks !
>> 
>>> //creating the voronoi
>>> v.voronoi input="Ind_rain_orig" output="Ind_rain_ker_vor"
>>> 
>>> //display the voronoi
>>> d.vect "Ind_rain_ker_vor"
>>> 
>>> http://n2.nabble.com/file/n3344342/Ind_rain_ker_vor.png 
>>> 
>> 
>> The problem is here, with v.voronoi, as you can see the white spots 
>> here. What do the original points (Ind_rain_orig) look like ?
>> 
>> I don't know the module well enough, but I think you might have hit a 
>> bug there (I've just tried a simple example for myself and also get 
>> weird white spots). Please file a report in the bug tracker.
>> 
>> 
>>> 
>>> //storing the area of each polygon to a csv file
>>> v.report ker_rain_vor_over option=area units=k >ker_area.csv --o
>> 
>> Note that you can use v.addcol and v.to.db upload the polygon areas to 
>> the attribute table.
>> 
>> Moritz
>> _______________________________________________
>> grass-user mailing list
>> grass-user at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/grass-user
>> 
>> 
> 
> 

-- 
View this message in context: http://n2.nabble.com/how-to-calculate-area-of-voronoi-polygons-considering-the-boundary-of-the-catchment-tp3335923p3345998.html
Sent from the Grass - Users mailing list archive at Nabble.com.