[GRASS-user] Obtain land use within 50 km buffers around vector points

[Johannes Radinger]

Thank you Moritz,

your suggestion using r.stats and the rasterized layer 2 of buffers works
really nice. It took me just a while to summarize and join all data and get
them back into the db in the right format. However, I think I managed this
task now. Thank you for your help!

I also think that either a correpondance table function and/or an
enhancement of v.rast.stat to work with overlapping buffers would be a
really nice enhancement.

On Thu, Jun 1, 2017 at 5:00 PM, Moritz Lennert <mlennert at club.worldonline.be
> wrote:

> On 01/06/17 16:41, Moritz Lennert wrote:
>
>> Currently, the best way I see is to create a correspondance table
>> between the pieces and the original cat values. You can get that by
>> running
>>
>> v.category buffers op=add layer=2 out=buffers_2_layers
>>
>
> [...]
>
> Then just run v.rast.stats once per class (each class raster can just be
>> a reclass of the original with classnum = 1\n* = NULL") on layer 2 of
>> the entire vector buffer map. Thus you will get the stats per piece of
>> buffer.
>>
>
> Instead of looping over the classes, you could also rasterize the layer 2
> of buffers with v.to.rast [...] use=cat and then run r.stats on the two
> layers:
>
> r.stats -c buffers,landuse
>
> Add the results as another temporary table to the db and use it plus the
> correspondance table to fill your original table.
>
> Moritz
>
>
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