[GRASS-user] r.quantile: what it exaclty do?

Dylan Beaudette dylan.beaudette at gmail.com
Fri Jan 2 14:40:50 EST 2009


On Fri, Jan 2, 2009 at 4:55 AM, Jarek Jasiewicz <jarekj at amu.edu.pl> wrote:
> Hi
> I tirend used r.quantile on SRTM data for Poland (min value about to 0, max
> value about to 2500 m a.s.l)
>
> r.quantile input=Polska at PERMANENT quantiles=4
> percentiles=0.001,0.01,0,1,0.25,0.50,0.75,0.90,0.99,0.999 bins=1000000
>
> and I recived:
>
> 0:0.000000:0.000000
> 1:0.001000:0.000000
> 2:0.010000:0.000000
> 3:0.250000:0.000000
> 4:0.500000:1.000000
> 5:0.750000:2.000000
> 6:0.900000:3.000000
> 7:0.990000:3.000000
> 8:0.999000:3.000000
> 9:1.000000:3.000000
>
> It looks like the results are divided by 1000 and rounded to the nearest
> integer.
>
> Did I something wrong?
>
> Jarek
>

I thought that the user supplies one of [quantiles=] | [percentiles=]
... could that be related to the odd output. I have verified (with R)
that r.quantile can compute correct quantiles... however, on my system
I need to set bins=100 or so, as the higher i set 'bins' odd things
would happen.

Glynn should know for sure.

Dylan


More information about the grass-user mailing list