[GRASS-user] shortest distance within a points layer

G. Allegri giohappy at gmail.com
Mon Aug 11 06:49:07 EDT 2008


It means that I have to select shortest distances from the distance
matrix from outside GRASS (because I can't use MIN, GROUP BY, and
similar statements with db.select with DBF driver), and then update
somehow the points attrbitutes from the previous selection... Mmm,
it's quite a common task, there should be something more
straightforward.

2008/8/11 Alex Mandel <tech_dev at wildintellect.com>:
> G. Allegri wrote:
>>
>> Hi lis
>> I need to evaluate the shortest distance between the points of the same
>> layer .
>> v.distance fails as to_map and from_map overlap (every shortest
>> distance is obviously 0: from point to itself). I was considering the
>> use of network analysis tools... but I don't see a straigthforward way
>> with them.
>>
>> Giovanni
>
> How about v.distance -a which creates a distance matrix then you can query
> the table for lowest value, group by point and exclude distances of 0.
> see http://www.grass.itc.it/gdp/html_grass63/v.distance.html
>
> Alex
>
>


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