[GRASS-dev] About v.distance, v.what.vect (wrt "count points within...").

[Moritz Lennert]

On 12/08/10 06:56, Nikos Alexandris wrote:
> So here you go using data from spearfish60 [1][2][3]
>
> # in grass64 using v.what.vect (makes no difference, right?) time
> v.what.vect --v vector=pareto_ref_points___pareto_ref_100m
> qvect=pareto_grid___OVER___ref_coi_points___pareto_grid___OVER___ref_100m___ON___classification_V___classification_1_200m
> column=gridcell_1 qcolumn=cat
>
[...]
>
> real    3m3.687s user    2m38.910s sys     0m2.400s
>
> # in grass70 before the latest update time v.distance --v
[...]
> real    3m4.270s user    2m43.140s sys     0m2.870s
>
> # in grass70 after the latest update ( I only did "make" within the
> /vector/v.distance directory - correct?)

yes

> real    3m5.339s user    2m42.780s sys     0m3.040s

[...]

AFAIU, MarkusM's change only affects dmax>0, so it's normal that you
don't see a difference.


> [2] map #2 v.info -t pareto_...<Very Long Name>
>
> nodes=26956 points=0 lines=0 boundaries=26955 centroids=6650
> areas=6650 islands=1 primitives=33605 map3d=0

So, you have 6000+ areas times 26000+ points.

>
> Hmmm... ? So, if use my 600000+ points maps, you can imagine why I
> report timings>20h.

You mean that it's normal that it takes so long, or that it is not
normal, and that's why we can imagine that you report it ? ;-)

Here's an attempt with a 100x100 grid (=10000 areas) and the 600000
points randomly created:

v.mkgrid mygrid n=100,100 --o
time v.distance from=mypoints at sqlite to=mygrid upload=to_attr
column=cat_municip to_column=cat dmax=0.0

real	2m22.505s

Moritz