[GRASS-user] v.net tools with polygons

[Daniel Victoria]

Ok Moritz,

Thanks for the tips. I'll try to go the centroids way

Cheers
Daniel

On Tue, Mar 3, 2015 at 5:35 AM, Moritz Lennert <mlennert at club.worldonline.be
> wrote:

> On 02/03/15 21:39, Daniel Victoria wrote:
>
>> Hi list,
>>
>> I'm beginning to learn and use the v.net <http://v.net> tools in Grass
>> in order to evaluate the distance from several crop fields to a
>> processing plant.
>>
>> I've successfully build the road network with the end nodes but now I'm
>> in doubt. My starting points in the analysis are crop fields, which are
>> polygons. So what is the best (or most common) practice?
>>
>> 1) Use the field centroids as starting nodes?
>> 2) Add field polygon boundaries to the network and run v.net.distance
>> backwards (from mill to fields)?
>> 3) Some other option?
>>
>
>
> I don't think that there is a best practice for this. It all depends on
> your application and the desired outcome. Do you want average time/distance
> from anywhere in the field to the plant ? Then probably the centroid is ok.
> Or do you want distance from the point of the field that is closest to the
> network ? Then you could get the coordinates of that point through
> v.distance (with upload=to_x,to_y) and use these points as nodes.
>
>
>
>  Also, if I'm to add the field boundaries to the network, how would I go
>> about it? Should I first v.patch the field with the roads layer and then
>> run v.net <http://v.net>?
>>
>
> Adding field boundaries still does not answer the question of where to put
> the start/stop point of your paths...
>
> If you want to add them to the network then yes, patching would be the
> best option, AFAIK.
>
> Moritz
>
>
>> Thanks
>> Daniel
>>
>>
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>>
>
>
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