[GRASS-dev] Area weighted rasterization with v.to.rast?

[Newcomb, Doug]

>r.mapcalculator to divide the value of each raster by the area of a raster
cell.
This should be divide the area of a cell by the value of the raster ( from
the polygon).  Sorry, no caffeine yet this morning.

Doug

On Thu, Nov 8, 2012 at 7:53 AM, Newcomb, Doug <doug_newcomb at fws.gov> wrote:

> Markus,
> The first thing that occurs to me is to make the value of the first raster
>  from the polygon layer the area of the polygon.  r.mapcalculator to divide
> the value of each raster by the area of a raster cell.  This should give
> you a raster with the value of the proportion of area of the polygon in
> each cell.
>
> Now rasterize the polygon layer with the original attribute you wanted to
> affect.  Multiply this raster by the proportional raster above.
>
> A bit brute force, but it should give you what you want.
>
> Doug
>
>
> On Thu, Nov 8, 2012 at 5:29 AM, Markus Neteler <neteler at osgeo.org> wrote:
>
>> Hi all,
>>
>> for a project I would be in need to rasterize vector polygons with
>> attribute value to the raster model where the resulting raster cells
>> carry the weighted portion of the original attribute according to
>> the area covered.
>>
>> Example:
>> A square vector polygon with value 10.000 falls onto four raster
>> cells. The resulting cells should each carry the value 2.500.
>>
>> I wonder if the mechanism used in r.resamp.stats for -w:
>>     Weight according to area
>> could be implemented in v.to.rast to achieve this goal.
>>
>> thanks
>> Markus
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>>
>
>
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