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 calculated
from
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 (top of
On Fri, Jun 21, 2013 at 10:04 PM, Nikos Alexandris
n...@nikosalexandris.net 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
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 can be
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 ;
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
nsres=73890
ewres=126390
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
nsres=73890
ewres=126390
-^^
ML:
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
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 * blue +
On Thu, Jun 20, 2013 at 6:24 PM, Nikos Alexandris
n...@nikosalexandris.net 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
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
-^^
rows and cols has precedence over
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 expected, but
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!
# with or
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, still gives,
On Mon, Jun 17, 2013 at 10:58 PM, Nikos Alexandris
n...@nikosalexandris.net 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
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
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'
784935 2695215
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
[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
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
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
---%--
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
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
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=2264.42037461018
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
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