[GRASS-user] i.atcorr: Returns empty raster
Abhishek Manandhar
abhishek.adams at gmail.com
Wed Mar 16 09:09:14 PDT 2016
Hello all,
I am using i.atcorr module of GRASS 7.0.4 release. I compiled the release,
as I wanted to add the Sentinel-2 sensor. So far, I was successful in
compiling the release. However, when I run atcorr, I get an empty raster
file. I have included the reports from r.info, i.atcorr and the parameters
below:
*r.info <http://r.info> output of the image*
(Wed Mar 16 16:38:39 2016)
r.info
map=S2A_OPER_MSI_L1C_TL_EPA__20160315T065417_A000920_T32TPS_B02 at PERMANENT
+----------------------------------------------------------------------------+
| Map: S2A_OPER_MSI_L1C_TL_EPA__2016 Date: Wed Mar 16 16:29:33 2016
|
| Mapset: PERMANENT Login of Creator: abheeman
|
| Location: munich
|
| DataBase: /media/abheeman/data/grassdata
|
| Title: ( S2A_OPER_MSI_L1C_TL_EPA__20160315T065417_A000920_T32TPS_B02
) |
| Timestamp: none
|
|----------------------------------------------------------------------------|
|
|
| Type of Map: raster Number of Categories: 0
|
| Data Type: CELL
|
| Rows: 10980
|
| Columns: 10980
|
| Total Cells: 120560400
|
| Projection: UTM (zone 32)
|
| N: 5200020 S: 5090220 Res: 10
|
| E: 709800 W: 600000 Res: 10
|
| Range of data: min = 0 max = *23562*
|
|
|
| Data Description:
|
| generated by r.in.gdal
|
|
|
| Comments:
|
| r.in.gdal -e input="/media/abheeman/data/grassdata/S2A_OPER_PRD_MSIL\
|
| 1C_PDMC_20160315T115050_R065_V20150826T102655_20150826T102655.SAFE/G\
|
| RANULE/S2A_OPER_MSI_L1C_TL_EPA__20160315T065417_A000920_T32TPS_N02.0\
|
| 1/IMG_DATA/S2A_OPER_MSI_L1C_TL_EPA__20160315T065417_A000920_T32TPS_B\
|
| 02.jp2" output="S2A_OPER_MSI_L1C_TL_EPA__20160315T065417_A000920_T32\
|
| TPS_B02" memory=300 offset=0
|
|
|
+----------------------------------------------------------------------------+
(Wed Mar 16 16:38:39 2016) Command finished (0 sec)
*i.atcorr verbose return*
(Wed Mar 16 16:39:48 2016)
i.atcorr -i -r --overwrite --verbose
input=S2A_OPER_MSI_L1C_TL_EPA__20160315T065417_A000920_T32TPS_B02 at PERMANENT
range=0,10000 parameters=/media/abheeman/data/grassdata/conf
output=munich_test_atcorr
* ****************************** 6s version 4.2b
****************************** *
* geometrical conditions identity
*
* -------------------------------
*
* Sentinel 2 observation
*
*
*
* month: 8 day: 26
*
* solar zenith angle: 39.16 deg solar azimuthal angle: 161.21 deg
*
* view zenith angle: 0.00 deg view azimuthal angle:0.00 deg
*
* scattering angle: 140.84 deg azimuthal angle difference: 161.21
deg
*
*
*
* atmospheric model description
*
* -----------------------------
*
* atmospheric model identity :
*
* tropical (uh2o=4.12g/cm2,uo3=.247cm-atm)
*
*
*
* aerosols type identity :
*
* Continental aerosols model
*
*
*
* optical condition identity :
*
* visibility : 13.00 km opt. thick. 550nm: 0.3516
*
*
*
* spectral condition
*
* ------------------
*
* sentinel_2 band1
*
* value of filter function :
*
* wl inf= 0.300 mic wl sup= 2.600mic
*
*
*
* target type
*
* -----------
*
* homogeneous ground
*
* constant reflectance over the spectra 0.000
*
*
*
* target elevation description
*
* ----------------------------
*
* ground pressure [mb] 954.77
*
* ground altitude [km] 0.520
*
* gaseous content at target level:
*
* uh2o= 3.227 g/cm2 uo3= 0.246 cm-atm
*
*
*
* atmospheric correction activated
*
* --------------------------------
*
Atmospheric correction...
Atmospheric correction complete.
(Wed Mar 16 16:39:59 2016) Command finished (10 sec)
*Parameters used*
20 - geometrical conditions=Sentinel-2
08 26 10.48 11.353693 48.200905 - month day hh.ddd longitude latitude
("hh.ddd" is in decimal hours GMT)
1 - atmospheric mode=tropical
1 - aerosols model=continental
13 - visibility [km] (aerosol model concentration)
-0.520 - mean target elevation above sea level [km]
(here 600m asl)
-786 - sensor height (here, sensor on board a
satellite)
129 - 1nd band of Sentinel-2A
*Note*
Before I invest more time in finding process to derive correct AOT and
chose appropriate atmospheric model, I wanted to give it a try with fake
parameters. As far as I understand, with fake parameter there should be
some short of false atmospheric correction. Therefore, there are false
values for atmospheric mode, aerosol model and visibility just for test
purpose.
*From r.info <http://r.info>, maximum value seems to be 23562. But the
value in sentinel bands can range only between 0-10000 currently, which
brings to the assumption that it probably could be noise. Will it affect
the result?*
*Some general questions:*
1. *For 6s parameter, it take geographic coordinate (I guess EPSG:4326)
as input. So, I was wondering if we also have transform the coordinate
system of the image to the same?*
2. *In my system, it took 10 seconds to process one image. But, I am not
sure if the processing time will remain same when the process outputs
non-empty file. My image size is 10980x10980 pixels. What is general
processing time it generally takes, for may be single Landsat-8 image ?*
3. *Regarding the raster with empty output, does anybody have
experienced such behavior recently? The discussions I searched mostly date
back to the time when Landsat-8 was not supported.*
If it helps, I am running grass in the computer with Ubuntu 14.04 system,
with 8 cores,16 gb ram and Intel Core i7-4790.
Regards,
Abhishek
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