[GRASSLIST:8922] Re: points in area

Markus Neteler neteler at itc.it
Mon Nov 7 11:25:51 EST 2005


On Mon, Nov 07, 2005 at 06:08:45PM +0100, Maik Trömel wrote:
> I thought of a faster solution ;-p
> 
> Are there any other statistic tools like r.univar. One which is able to 
> make a selection? Something like: "Make a statistik of all points lying 
> in area "a"!" (without extracting and selecting before)

OK, I have added a 'where' option to v.univar:

Spearfish example:

v.univar fields col=cat where='cat>10 AND cat < 20'
WARNING: Incompatible vector type(s), only number of features, minimum,
         maximum and range can be calculated
number of features with non NULL attribute: 18
number of missing attributes: 108
number of NULL attributes: 0
minimum: 11
maximum: 19
range: 8

Using the new v.what.vect script (submitted this morning) you could add
a new column "areacat" to the points map and upload the area categories (IDs)
to the points map. Then use the modified v.univar and select only the
area of interest.

Sounds better?

Markus

 
> Maik
> 
> 
> 
> Markus Neteler wrote:
> 
> >Maik,
> >
> >please define "better solution"...
> >
> >Markus
> >
> >On Mon, Nov 07, 2005 at 05:06:52PM +0100, Maik Trömel wrote:
> > 
> >
> >>I thought of this too. But I hoped there would be a better solution.
> >>
> >>Markus Neteler wrote:
> >>
> >>   
> >>
> >>>Maik Trömel wrote:
> >>>
> >>>
> >>>
> >>>     
> >>>
> >>>>I think my question is not clear enough.
> >>>>I know there's possibility to get points lying in an area with v.select.
> >>>>In my map i've got several areas. I need all points lying in area a to
> >>>>make a statistic with v.univar. But with v.select there is only the
> >>>>possibility to get all points lying in all areas. That's not what I 
> >>>>need.
> >>>> 
> >>>>
> >>>>       
> >>>>
> >>>Simply first extract area 'a' with v.extract, then run v.select on this
> >>>new map.
> >>>For several areas it's best to write a small script which loops over the
> >>>area map,
> >>>extracts, selects, and runs v.univer.
> >>>
> >>>hope this helps
> >>>Markus
> >>>
> >>>
> >>>
> >>>     
> >>>
> >
> > 
> >
> 

-- 
Markus Neteler     <neteler itc it>       http://mpa.itc.it
ITC-irst -  Centro per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
Via Sommarive, 18        -       38050 Povo (Trento), Italy




More information about the grass-user mailing list