MM:
> >> >> I think I figured it out: The EVI formula in i.vi is for MODIS.
NA:
> >> > That's precise, EVI is MODIS specific. We should clearly describe this
> >> > in the manual (I will try to alter the respective text).
MM:
> >> From the literature, I gor the impression that EVI can be calcul
Markus Metz wrote:
>
> I am pretty sure that the EVI2 formula in i.vi is not cross-sensor,
> but also tailored to unscaled MODIS input bands:
>
> EVI2 = G * ( nir - red) / (nir + C1 * red + L)
Hmm, no, it seems that the coefficients for both EVI and EVI2 are
meant for scaled MODIS input bands (to
On Fri, Jun 21, 2013 at 10:04 PM, Nikos Alexandris
wrote:
> Markus Metz wrote:
>> >> I think I figured it out:
>> >> The EVI formula in i.vi is for MODIS.
>
> Nikos A:
>> > That's precise, EVI is MODIS specific. We should clearly describe this in
>> > the manual (I will try to alter the respectiv
Markus, and whom this is of interest,
do you care for a small diff for the manual?
Like,
- replace the reference (as you suggested)
- mention that "EVI is not consistent across different sensors due to its
requirement for a blue-band input" [0]
Nikos
---
[0] Zhangyan Jiang ; Alfredo R. Huete
Markus Metz wrote:
> >> I think I figured it out:
> >> The EVI formula in i.vi is for MODIS.
Nikos A:
> > That's precise, EVI is MODIS specific. We should clearly describe this in
> > the manual (I will try to alter the respective text).
MM:
> From the literature, I gor the impression that EVI c
On Thu, Jun 20, 2013 at 6:24 PM, Nikos Alexandris
wrote:
> Markus Metz wrote:
>
>> I think I figured it out:
>
>> The EVI formula in i.vi is for MODIS.
>
> That's precise, EVI is MODIS specific. We should clearly describe this in the
> manual (I will try to alter the respective text).
>From the
Markus Metz wrote:
> I think I figured it out:
> The EVI formula in i.vi is for MODIS.
That's precise, EVI is MODIS specific. We should clearly describe this in the
manual (I will try to alter the respective text).
> The generic formula is
>
> G * ( nir - red) / (nir + C1 * red - C2 * blu
I think I figured it out:
The EVI formula in i.vi is for MODIS. The generic formula is
G * ( nir - red) / (nir + C1 * red - C2 * blue + L)
where G is a gain factor, C1, C2 are coefficients to correct for
aerosol influences in the red band using the blue band and L is the
canopy background adjus
Nikos Alexandris wrote:
> >> >> > g.region -pagc e=784935 n=2695215 rows=1 cols=1 res=30
> >> >
> >> > ^^---^^^--^--^-^^
> >> >
> >> >> > n=2695230
> >> >> > s=2621340
> >> >> > w=658560
> >> >> > e=784950
> >> >
> >> > -v
> >> >
> >> >> > ns
On Wed, June 19, 2013 23:34, Nikos Alexandris wrote:
> Moritz Lennert wrote:
>
>> >> > g.region -pagc e=784935 n=2695215 rows=1 cols=1 res=30
>> > ^^---^^^--^--^-^^
>
>> >> > n=2695230
>> >> > s=2621340
>> >> > w=658560
>> >> > e=784950
>
>> > -v
Markus M:
> >> 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] ---
O-K, let's get this from the start (if there is still energy...).
First thing: the region!
# w
Markus Metz wrote:
..
> > 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 expect
Moritz Lennert wrote:
> >> > g.region -pagc e=784935 n=2695215 rows=1 cols=1 res=30
> > ^^---^^^--^--^-^^
> >> > n=2695230
> >> > s=2621340
> >> > w=658560
> >> > e=784950
> > -v
> >> > nsres=73890
> >> > ewres=126390
> > -^^
> row
On Mon, Jun 17, 2013 at 10:58 PM, Nikos Alexandris
wrote:
> 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.ma
On Mon, June 17, 2013 22:58, Nikos Alexandris wrote:
> 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,
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 exp
[all deleted]
I did several tests but I don't want to add more "noise" in this thread.
The "problem" boils down to when using the full extent of the map(s), e.g.
an "out-of-range" max value (in one or in a few pixels) appears. When using
single-pixels, all is fine.
Nikos
__
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. Obviously, there is a bug in i.vi. Furthermore, i.vi is
slower than r.mapcalc. I recommend to replace the C module i.vi with a
i.vi script that calls
Nikos Alexandris wrote:
> > > I get an unexpected range of evi values using "i.vi" (G7), i.e.
[..]
> > > # range is...
> > > r.info -r evi
> > > min=-6912.82161611806
> > > max=2264.42037461018
[..]
> Looking for these pixels, e.g.
>
> r.stats evi_ToAR -g | grep '\-5905'
>
>
Nikos Alexandris wrote:
> > I get an unexpected range of evi values using "i.vi" (G7), i.e.
> > # derive EVI
> > i.vi viname=evi red=B.Trimmed.ToAR.3 blue=B.Trimmed.ToAR.1
> > nir=B.Trimmed.ToAR.4 output=evi
> > # range is...
> > r.info -r evi
> > min=-6912.821616
Markus Neteler wrote:
> if you have a i.landsat.toar corrected scene, please extract the
> values for
Landsat scene: LE71610432005160ASN00
> - water pixel
e.g. WaterCoordinates=765525.446097,2756869.46097
# DNs
r.what
map=B.Trimmed.1,B.Trimmed.2,B.Trimmed.3,B.Trimmed.4,B.Trimmed.5,B.Trimmed.
Markus Neteler wrote:
> Hi Nikos,
Salut!
> if you have a i.landsat.toar corrected scene, please extract the values for
--%<---
I have to report-back, though, that using corrected (DOS1) bands (==
reflectances), EVI looks OK!, i.e.
min = -1.27297025550878 max = 1.4896100159326
--->%--
Hi Nikos,
if you have a i.landsat.toar corrected scene, please extract the values for
- water pixel
- green vegetation
- asphalt
... all bands except for TIR.
I want then to synthetic channels of one pixel to do
the i.vi testing:
# prepare comp. region
g.region rast=lsat7_2002_10 rows=1 cols=1
Nikos Alexandris wrote:
> I get an unexpected range of evi values using "i.vi" (G7), i.e.
>
> # derive EVI
> i.vi viname=evi red=B.Trimmed.ToAR.3 blue=B.Trimmed.ToAR.1
> nir=B.Trimmed.ToAR.4 output=evi
>
> # range is...
> r.info -r evi
>
> min=-6912.82161611806
>
Hi devs.
I get an unexpected range of evi values using "i.vi" (G7), i.e.
# derive EVI
i.vi viname=evi red=B.Trimmed.ToAR.3 blue=B.Trimmed.ToAR.1
nir=B.Trimmed.ToAR.4 output=evi
# range is...
r.info -r evi
min=-6912.82161611806
max=2264.4203746101
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