[GRASS-user] Regarding Atmospheric Correction Model Output
iat bd
imtiazataher at gmail.com
Sat Nov 14 18:57:57 PST 2015
Date: November 15, 2015
Hi All,
Following are my procedure, observation and question/ request:
Data Source: Earth Explorer Landsat 8
Grass GIS Version: 7.0.2 RC1
Windows 7 32 bit OS
I have been trying to conduct an Atmospheric correction using the Grass
wiki reference
https://grasswiki.osgeo.org/wiki/Atmospheric_correction
https://grass.osgeo.org/grass64/manuals/i.atcorr.html
https://grass.osgeo.org/grass64/manuals/i.landsat.toar.html
Step 01:
I skipped using the Toar Tool and used Raster map calculator to generate
a). Reflectance = REFLECTANCE_MULT_BAND_X*DN + REFLECTANCE_ADD_BAND_X
b). Reflectance with correction of sun angle = Reflectance/ Sin(Ɵ)
Step 02:
Plugged in to i.atcorr the Reflectance bands generated at Step 01 for band
4, 3, 2 amd 8 along with their respective control file.
Step 03: IHS Pan Sharpened band 4,3,2 with band 8
Step 04: Generated a RGB composite using Red = band 4, Green = band 3 and
Blue = band 2.
I am attaching the resultant image and original unadjusted 432 composites
for comparison. Obviously, I missed something. Atmospherically adjusted
Image should’ve been clearer. Its not even looking like an RGB image.
Also attaching the Command outputs so that you may follow my steps, to
notice if there was anything unusual and a control file for reference. I
used Tropical Atmospheric model and Urban Aerosol model. The values used in
the control file were collected from Atmospheric correction wiki.
I’ll appreciate it if anyone of you can share your insight and tell me how
I can get a correct atmospherically adjusted image. Also, I noticed there
is no longer any i.landsat.dehaze extension available. Could you please
tell me how dehazing may be possible absent the extension?
Do let me know if there is anything missing or not clearly explained.
Thanks in advance.
Regards,
Imtiaz
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Atmospheric Correction Band 4
(Fri Nov 13 23:54:00 2015)
i.atcorr -r --verbose input=TOAR_B4 at TOAR parameters=E:\LandCover_Classification\Aeronet\Atcorr_B4.txt output=ATM_B4
* ****************************** 6s version 4.2b
****************************** *
* geometrical conditions identity
*
* -------------------------------
*
* Landsat 8 observation
*
*
*
* month: 10 day: 27
*
* solar zenith angle: 40.69 deg solar azimuthal angle:
150.19 deg *
* view zenith angle: 0.00 deg view azimuthal angle:
0.00 deg *
* scattering angle: 139.31 deg azimuthal angle
difference: 150.19 deg *
*
*
* atmospheric model description
*
* -----------------------------
*
* atmospheric model identity :
*
* tropical (uh2o=4.12g/cm2,uo3
=.247cm-atm) *
*
*
* aerosols type identity :
*
* Urban aerosols model
*
*
*
* optical condition identity :
*
* visibility : 7.54 km opt. thick. 550nm
: 0.5500 *
*
*
* spectral condition
*
* ------------------
*
* Landsat 8 Red
*
* value of filter function :
*
* wl inf= 0.626 mic wl sup= 0.682
mic *
*
*
* target type
*
* -----------
*
* homogeneous ground
*
* constant reflectance over the spectra
0.000 *
*
*
* target elevation description
*
* ----------------------------
*
* ground pressure [mb] 1012.54
*
* ground altitude [km] 0.004
*
* gaseous content at target level:
*
* uh2o= 4.110 g/cm2 uo3= 0.248
cm-atm *
*
*
* atmospheric correction activated
*
* --------------------------------
*
Atmospheric correction...
Atmospheric correction complete.
(Fri Nov 13 23:56:08 2015) Command finished (2 min 8 sec)
Atmospheric Correction Band 3
(Sat Nov 14 00:04:55 2015)
i.atcorr -r --verbose input=TOAR_B3 at TOAR parameters=E:\LandCover_Classification\Aeronet\Atcorr_B3.txt output=ATM_B3
* ****************************** 6s version 4.2b
****************************** *
* geometrical conditions identity
*
* -------------------------------
*
* Landsat 8 observation
*
*
*
* month: 10 day: 27
*
* solar zenith angle: 40.69 deg solar azimuthal angle:
150.19 deg *
* view zenith angle: 0.00 deg view azimuthal angle:
0.00 deg *
* scattering angle: 139.31 deg azimuthal angle
difference: 150.19 deg *
*
*
* atmospheric model description
*
* -----------------------------
*
* atmospheric model identity :
*
* tropical (uh2o=4.12g/cm2,uo3
=.247cm-atm) *
*
*
* aerosols type identity :
*
* Urban aerosols model
*
*
*
* optical condition identity :
*
* visibility : 7.54 km opt. thick. 550nm
: 0.5500 *
*
*
* spectral condition
*
* ------------------
*
* Landsat 8 Green
*
* value of filter function :
*
* wl inf= 0.513 mic wl sup= 0.600
mic *
*
*
* target type
*
* -----------
*
* homogeneous ground
*
* constant reflectance over the spectra
0.000 *
*
*
* target elevation description
*
* ----------------------------
*
* ground pressure [mb] 1012.54
*
* ground altitude [km] 0.004
*
* gaseous content at target level:
*
* uh2o= 4.110 g/cm2 uo3= 0.248
cm-atm *
*
*
* atmospheric correction activated
*
* --------------------------------
*
Atmospheric correction...
Atmospheric correction complete.
(Sat Nov 14 00:06:28 2015) Command finished (1 min 32 sec)
Atmospheric Correction Band 2
(Sat Nov 14 00:12:59 2015)
i.atcorr -r --verbose input=TOAR_B2 at TOAR parameters=E:\LandCover_Classification\Aeronet\Atcorr_B2.txt output=ATM_B2
* ****************************** 6s version 4.2b
****************************** *
* geometrical conditions identity
*
* -------------------------------
*
* Landsat 8 observation
*
*
*
* month: 10 day: 27
*
* solar zenith angle: 40.69 deg solar azimuthal angle:
150.19 deg *
* view zenith angle: 0.00 deg view azimuthal angle:
0.00 deg *
* scattering angle: 139.31 deg azimuthal angle
difference: 150.19 deg *
*
*
* atmospheric model description
*
* -----------------------------
*
* atmospheric model identity :
*
* tropical (uh2o=4.12g/cm2,uo3
=.247cm-atm) *
*
*
* aerosols type identity :
*
* Urban aerosols model
*
*
*
* optical condition identity :
*
* visibility : 7.54 km opt. thick. 550nm
: 0.5500 *
*
*
* spectral condition
*
* ------------------
*
* Landsat 8 Blue
*
* value of filter function :
*
* wl inf= 0.436 mic wl sup= 0.527
mic *
*
*
* target type
*
* -----------
*
* homogeneous ground
*
* constant reflectance over the spectra
0.000 *
*
*
* target elevation description
*
* ----------------------------
*
* ground pressure [mb] 1012.54
*
* ground altitude [km] 0.004
*
* gaseous content at target level:
*
* uh2o= 4.110 g/cm2 uo3= 0.248
cm-atm *
*
*
* atmospheric correction activated
*
* --------------------------------
*
Atmospheric correction...
Atmospheric correction complete.
(Sat Nov 14 00:14:32 2015) Command finished (1 min 32 sec)
Atmospheric Correction Band 8
(Sat Nov 14 00:17:58 2015)
i.atcorr -r --verbose input=TOAR_B8 at TOAR parameters=E:\LandCover_Classification\Aeronet\Atcorr_B8.txt output=ATM_B8
* ****************************** 6s version 4.2b
****************************** *
* geometrical conditions identity
*
* -------------------------------
*
* Landsat 8 observation
*
*
*
* month: 10 day: 27
*
* solar zenith angle: 40.69 deg solar azimuthal angle:
150.19 deg *
* view zenith angle: 0.00 deg view azimuthal angle:
0.00 deg *
* scattering angle: 139.31 deg azimuthal angle
difference: 150.19 deg *
*
*
* atmospheric model description
*
* -----------------------------
*
* atmospheric model identity :
*
* tropical (uh2o=4.12g/cm2,uo3
=.247cm-atm) *
*
*
* aerosols type identity :
*
* Urban aerosols model
*
*
*
* optical condition identity :
*
* visibility : 7.54 km opt. thick. 550nm
: 0.5500 *
*
*
* spectral condition
*
* ------------------
*
* Landsat 8 Panchromatic
*
* value of filter function :
*
* wl inf= 0.488 mic wl sup= 0.692
mic *
*
*
* target type
*
* -----------
*
* homogeneous ground
*
* constant reflectance over the spectra
0.000 *
*
*
* target elevation description
*
* ----------------------------
*
* ground pressure [mb] 1012.54
*
* ground altitude [km] 0.004
*
* gaseous content at target level:
*
* uh2o= 4.110 g/cm2 uo3= 0.248
cm-atm *
*
*
* atmospheric correction activated
*
* --------------------------------
*
Atmospheric correction...
Atmospheric correction complete.
(Sat Nov 14 00:19:53 2015) Command finished (1 min 54 sec)
Pan Sharpening
(Sat Nov 14 00:23:58 2015)
i.pansharpen --verbose red=ATM_B4 at TOAR green=ATM_B3 at TOAR blue=ATM_B2 at TOAR pan=ATM_B8 at TOAR output=PAN_RGB method=ihs
Performing pan sharpening with hi res pan image: 15.000000
Using IHS<->RGB algorithm
Transforming to IHS color space...
Histogram matching...
Transforming back to RGB color space and sharpening...
Assigning grey equalized color tables to output images...
The following pan-sharpened output maps have been generated:
PAN_RGB_red
PAN_RGB_green
PAN_RGB_blue
To visualize output, run: g.region -p raster=PAN_RGB_red
d.rgb r=PAN_RGB_red g=PAN_RGB_green b=PAN_RGB_blue
If desired, combine channels into a single RGB map with 'r.composite'.
Channel colors can be rebalanced using i.colors.enhance.
Group <PAN_RGB> does not yet exist. Creating...
Adding raster maps to group <PAN_RGB>...
Adding raster map <PAN_RGB_red at TOAR> to group
Adding raster map <PAN_RGB_blue at TOAR> to group
Adding raster map <PAN_RGB_green at TOAR> to group
(Sat Nov 14 00:26:31 2015) Command finished (2 min 32 sec)
Composite
(Sat Nov 14 00:31:31 2015)
r.composite --verbose red=PAN_RGB_red at TOAR green=PAN_RGB_green at TOAR blue=PAN_RGB_blue at TOAR output=RGB_PAN.tif
Creating color table for output raster map...
Writing raster map <RGB_PAN.tif>...
r.composite complete. Raster map <RGB_PAN.tif> created.
(Sat Nov 14 00:32:04 2015) Command finished (33 sec)
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18
10 27 4.41 90.373 23.113
1
3
0
0.55
-0.004
-1000
116
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