[ back again... :-) ]
Nikos wrote:
Downloaded:
- extra: LT50160351988258XXX03 (includes visible clouds - maybe good for
testing?)
Hamish:
in the GloVis preview I only see a few clouds in the NE corner
for that date. (Sept 14, 1988)
Right. I specifically selected a scene with a few
Nikos wrote:
Downloaded:
- extra: LT50160351988258XXX03 (includes visible
clouds - maybe good for testing?)
in the GloVis preview I only see a few clouds in the NE corner
for that date. (Sept 14, 1988)
Maybe 1991/10/25 is another good scene for a cloud test? (looks
like 20% high cumulus
Nikos:
...
Downloaded:
- extra: LT50160351988258XXX03 (includes visible clouds - maybe good for
testing?)
# import landsat bands in wgs84, utm, zone 17
# r.proj to nc_spm_08/landsat
# set region
g.region rast=lsat5_1988.1 -p
projection: 99 (Lambert Conformal Conic)
zone: 0
datum:
On Friday 17 of September 2010 22:27:40 Hamish wrote:
Nikos wrote:
Given that the NC lsat data set represents untouched DN's,
does it?
We'll nail that one... ;-)
perhaps it has to do with old vs new calibration parameters?
at least for the lsat7_2000 NC maps, the cloud detection is
Hamish:
I think we'll have to redownload the three NC scenes from GloVis
to know for sure.
Nikos:
Downloaded:
- LT50160351987287XXX08
The metadata given in Glovis [1] (there is an option show metadata) do not
agree with the ones provided in the file L5016035_03519871014_MTL.txt [2]
Nikos:
Note that the LC lsat5 rasters are of 28.5m while the currently available
at usgs is of 30m pix-res. I just kept the 28.5 (when reprojecting the
usgs-lsat5 to the nc_spm_08 location)
Again:
Note that the _NC_ lsat5 rasters are of 28.5m while the currently available at
usgs are of
Hamish:
Probably we should concentrate on the North Carolina dataset for common
tests... its landsat mapset has:
...
Auto-cloud determination for the NC 1987 Landsat5 scene is no good.
Right, it does not look good.
# rename lsat5_1987_10 to lsat5_1987.1 (same for the rest of the bands of
Nikos wrote:
Given that the NC lsat data set represents untouched DN's,
does it?
perhaps it has to do with old vs new calibration parameters?
at least for the lsat7_2000 NC maps, the cloud detection is also
very bad, and there I confirmed the calibration numbers with the
values listed in the
Hamish:
should we be calculating the sat_zenith= param from
SUN_AZIMUTH in the metadata file, or is that something
else? I just used the default 8.2 deg.
Nikos:
Good question! As described above, for the sake of testing
I just fed the sat_zenith parameter the sun_azimuth value
Hamish:
[...]
band 6 temperatures do not look very plausible (30 degC ocean and -6 degC
land) on a sunny autumn day.
here
http://landsathandbook.gsfc.nasa.gov/handbook/handbook_htmls/chapter11/chapter11.html
something relevant I guess (11.3.3 Band 6 Conversion to Temperature)
Nikos
Nikos wrote:
... I realised that I don't really have the correct metadata file for
the scene I was given. The meta file available at Glovis is not really
the complete set of meta-information (is my guess -- missing
sat_zenith= value for example).
Hamish wrote:
fwiw with Landsat-7
Nikos:
# so, here it goes... seems to run fine
i.landsat.toar band_prefix=landsat_postfire_east_sterea_ellas
method=uncorrected sensor=5 date=2007-09-05 solar_elevation=52.4986238
product_date=2007-09-05
...
r.info landsat_postfire_east_sterea_ellas.toar.6 -r
min=203.36601783578
Nikos:
# so, here it goes... seems to run fine
i.landsat.toar band_prefix=landsat_postfire_east_sterea_ellas
method=uncorrected sensor=5 date=2007-09-05 solar_elevation=52.4986238
product_date=2007-09-05
...
r.info landsat_postfire_east_sterea_ellas.toar.6 -r
min=203.36601783578
Nikos:
# so, here it goes... seems to run fine
i.landsat.toar band_prefix=landsat_postfire_east_sterea_ellas
method=uncorrected sensor=5 date=2007-09-05 solar_elevation=52.4986238
product_date=2007-09-05
...
r.info landsat_postfire_east_sterea_ellas.toar.6 -r
Nikos wrote:
# with -f
not sure about the real differences with the previous command. Look fine
though :-)
the paper states that the filtering will convert pixels which have 5 of 8
surrounding cells as clouds into a cloud pixel as well, thus removing small
holes. I have not checked if the
Hi,
I've just made some small changes to i.landsat.acca and i.landsat.toar in
svn which shouldn't change the behaviour of the module at all, just do
some more error checks and make better use of libgis (writes out more
metadata etc. e.g. added units=Kelvin to band 6 metadata, not sure about
W/m^2
Hamish:
Probably we should concentrate on the North Carolina
dataset for common tests... its landsat mapset has:
...
lsat7_2000_10
lsat7_2000_20
lsat7_2000_30
lsat7_2000_40
lsat7_2000_50
lsat7_2000_61
lsat7_2000_70
lsat7_2000_80
metadata from hist/ file:
Hamish wrote:
should we be calculating the sat_zenith= param from
SUN_AZIMUTH in the metadata file, or is that something
else? I just used the default 8.2 deg.
Nikos:
Good question! As described above, for the sake of testing
I just fed the sat_zenith parameter the sun_azimuth value
and
Nikos wrote:
... I realised that I don't really have the correct metadata file for
the scene I was given. The meta file available at Glovis is not really
the complete set of meta-information (is my guess -- missing
sat_zenith= value for example).
fwiw with Landsat-7 downloads from GloVis I
Hi Nikos,
I did not use i.landsat.toar. I converted the DN values to radiance
manually, using r.mapcalc and the formula and coefficients provided.
Are you going to use i.atcorr? I'm still trying to figure out which is
the correct procedure for i.atcorr:
1) Convert DN to radiance and run
Those are digital numbers.
On Mon, Sep 13, 2010 at 6:38 AM, Daniel Victoria
daniel.victo...@gmail.com wrote:
Hi Nikos,
I did not use i.landsat.toar. I converted the DN values to radiance
manually, using r.mapcalc and the formula and coefficients provided.
Are you going to use i.atcorr? I'm
Nikos:
Did you finally used i.landsat.toar for the Landsat5 - TM bands?
I haven't tried with landsat 5 data from glovis yet, have some scenes
on order, expect them to arrive in the next few days. It seems to be
working for me with landsat7 data. Band 61 temperatures seem plausible
anyway
Daniel Victoria wrote:
I did not use i.landsat.toar. I converted the DN values to radiance
manually, using r.mapcalc and the formula and coefficients provided.
ok
Are you going to use i.atcorr?
Currently I only require to automatically detect clouds and nothing more than
that. Since I
On Monday 13 of September 2010 04:20:33 stephen sefick wrote:
I have to go out in the field tomorrow, but I have put together a
script, semi-automatically, to do this and calculate NDVI. I can pass
it along for what it is worth.
Sure, and if it's generally helpful we might put that in the
Nikos:
Did you finally used i.landsat.toar for the Landsat5 - TM bands?
Hamish:
I haven't tried with landsat 5 data from glovis yet, have some scenes
on order, expect them to arrive in the next few days. It seems to be
working for me with landsat7 data. Band 61 temperatures seem plausible
Daniel Victoria:
I haven't tryed i.landsat.toar addon but from what I read in the wiki
(http://grass.osgeo.org/wiki/Atmospheric_correction) I could either
use i.landsat.toar or a DN - Radiance conversion formula that is
given...
Will try to recalculate the images, I might have done
I have to go out in the field tomorrow, but I have put together a
script, semi-automatically, to do this and calculate NDVI. I can pass
it along for what it is worth.
On Sun, Sep 12, 2010 at 7:35 PM, Nikos Alexandris
nikos.alexand...@felis.uni-freiburg.de wrote:
Daniel Victoria:
I haven't
Hi all,
I'm trying to estimate albedo from landsat5 images but I'm getting
very strange result. Water bodies, for instance, are giving me an
albedo of 0.15 to 0.17, unusualy high.
Here is the procedure I'm doing
1) Convert TM images from grey level to radiance using the Lmax / Lmin
formula
Hey Daniel
I think the input map to be given in i.atcorr should not be the DN.
Conversion to radiance or reflectance should be done before implementing the
6s algorithm. Have you tried i.landsat.toar to obtain radiance values?
Success!
JM
2010/8/2 Daniel Victoria daniel.victo...@gmail.com
Hi Jose,
I haven't tryed i.landsat.toar addon but from what I read in the wiki
(http://grass.osgeo.org/wiki/Atmospheric_correction) I could either
use i.landsat.toar or a DN - Radiance conversion formula that is
given...
Will try to recalculate the images, I might have done something wrong
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