Dear all,
I am trying to use i.atcorr in GRASS GIS 7 with AVNIR-2 data in Japan, it works well for band 1,4 but returns all NULL values for band 2,3. Maybe the problem is because of Sensor band parameter (the last one in 6S parameters, the values are 81, 82. 83, 84 respectively band 1, 2, 3, 4): For all 4 bands, I change the parameter from 81 to 84, it returns all NULL values when the parameter is 82 or 83; real/integer values when the parameter is 81 or 84. Below is list of 6S parameters for band 2:
11 # geometrical conditions = avnir
2 15 3.00 135.657 34.282 # month day hh.ddd long lat
1 # atmospheric mode = tropical
1 # aerosols model = continental
11 # visibility (km)
-0.300 # mean target elevation above sea level = 300 m
-1000 # sensor height = on board
82 # 2th band of avnir
Could anybody help me to solve this problem? Thank you very much.
···
Yours sincerely,
Hang
Do Thi Hang (MSc candidate)
GIS Laboratory
Graduate school for Creative Cities
Osaka City University
Tel. +81-90-8385-6238
Dear Hang,
On Fri, Jul 29, 2016 at 7:38 AM, Do Thi Hang <dohanghumg@gmail.com> wrote:
Dear all,
I am trying to use i.atcorr in GRASS GIS 7 with AVNIR-2 data in Japan, it
works well for band 1,4 but returns all NULL values for band 2,3. Maybe the
problem is because of Sensor band parameter (the last one in 6S parameters,
the values are 81, 82. 83, 84 respectively band 1, 2, 3, 4): For all 4
bands, I change the parameter from 81 to 84, it returns all NULL values when
the parameter is 82 or 83; real/integer values when the parameter is 81 or
84.
A question: are your AVNIR-2 input data representing radiance at
top-of-atmosphere (TOA)?
Below is list of 6S parameters for band 2:
11 # geometrical conditions = avnir
2 15 3.00 135.657 34.282 # month day hh.ddd long lat
1 # atmospheric mode = tropical
1 # aerosols model = continental
11 # visibility (km)
-0.300 # mean target elevation above sea
level = 300 m
-1000 # sensor height = on board
82 # 2th band of avnir
Could anybody help me to solve this problem? Thank you very much.
While I haven't worked with AVNIR-2 yet, I don't see any obvious
errors in the file. Not sure about "tropical" for Osaka but it should
deliver some result anyway.
However, in the first place let's check the input data.
Can you post the range of each channel here? (r.info output contains it).
Best,
Markus
--
Markus Neteler
http://www.mundialis.de - free data with free software
http://grass.osgeo.org
http://courses.neteler.org/blog
Dear Mr Markus,
Yes, the inputs were converted to TOA radiance by using formular: Rad = DN*Gain + Offset, range of 4 bands:
band 1: min = 42.336 max = 149.94 (Comments: b1 * 0.588
band 2: min = 25.212 max = 146.115 (Comments: b2 * 0.573)
band 3: min = 15.562 max = 128.01 (Comments: b3 * 0.502)
band 4: min = 11.14 max = 124.768 (Comments: b4 * 0.557)
When I try with input which presents TOA reflectance and use “i.atcorr -r”, it also returns all NULL values for band 2,3.
Attachments are orginal band 2 (b2) and TOA radiance of band 2 (b2_rad).
Thank you so much for your support.
b2_rad
b2
···
2016-08-04 0:49 GMT+09:00 Markus Neteler <neteler@osgeo.org>:
Dear Hang,
On Fri, Jul 29, 2016 at 7:38 AM, Do Thi Hang <dohanghumg@gmail.com> wrote:
Dear all,
I am trying to use i.atcorr in GRASS GIS 7 with AVNIR-2 data in Japan, it
works well for band 1,4 but returns all NULL values for band 2,3. Maybe the
problem is because of Sensor band parameter (the last one in 6S parameters,
the values are 81, 82. 83, 84 respectively band 1, 2, 3, 4): For all 4
bands, I change the parameter from 81 to 84, it returns all NULL values when
the parameter is 82 or 83; real/integer values when the parameter is 81 or
84.
A question: are your AVNIR-2 input data representing radiance at
top-of-atmosphere (TOA)?
Below is list of 6S parameters for band 2:
11 # geometrical conditions = avnir
2 15 3.00 135.657 34.282 # month day hh.ddd long lat
1 # atmospheric mode = tropical
1 # aerosols model = continental
11 # visibility (km)
-0.300 # mean target elevation above sea
level = 300 m
-1000 # sensor height = on board
82 # 2th band of avnir
Could anybody help me to solve this problem? Thank you very much.
While I haven’t worked with AVNIR-2 yet, I don’t see any obvious
errors in the file. Not sure about “tropical” for Osaka but it should
deliver some result anyway.
However, in the first place let’s check the input data.
Can you post the range of each channel here? (r.info output contains it).
Best,
Markus
–
Markus Neteler
http://www.mundialis.de - free data with free software
http://grass.osgeo.org
http://courses.neteler.org/blog
Yours sincerely,
Hang
Do Thi Hang (MSc candidate)
GIS Laboratory
Graduate school for Creative Cities
Osaka City University
Tel. +81-90-8385-6238