[GRASS-dev] Unexpected EVI range from "i.vi"

[Nikos Alexandris]

Markus Metz wrote:

> Feeding the test values and the evi(2) formula to r.mapcalc, the
> results are more or less in the expected range, still beyond [-1, 1],
> but not much.

[cut]

Yes, but feeding the "suspect" values in r.mapcalc, still gives, correctly, 
large/out of range (regarding EVI's expected range) result(s).

Anyhow, just to have a quick-check on "r.what", should I upload the bands in 
question somewhere?  Would anyone have the time to explain/check why r.what 
gives different results depending on the extent/resolution for the same 
coordinates?  Which, might be expected, but why does "g.region rows=1 cols=1" 
set the resolution to... see below:

Nikos

 
Nikos Alexandris:

[snip]

> > Now, "pointing" to the suspect pixel:
> > 
> > # both res=30  &  res=1 give the same result, of course
> > g.region -pagc e=784935 n=2695215 rows=1 cols=1 res=30
-------------------------------------------^------^-----^^
> > 
> > n=2695230
> > s=2621340
> > w=658560
> > e=784950

----------vvvvvv
> > nsres=73890
> > ewres=126390
----------^^^^^^

> > rows=1
> > cols=1
> > cells=1
> > center_easting=721755.000000
> > center_northing=2658285.000000
> > 
> > # what is there?
> > r.what coordinates=784935,2695215
> > map=B.Trimmed.ToAR.1,B.Trimmed.ToAR.3,B.Trimmed.ToAR.4,evi_DN,evi_ToAR
> > 
> > 784935|2695215||0.264138088849702|0.372703389833447|
> > 0.438437054236573|-0.203045685279188|0.0970312073830427
> > 
> > [..]
> > 
> > I guess it has to do with the extent/res definitions...