5

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

  • Step 01:

    I skipped using the Toar Tool and used Raster map calculator to generate:

    a). Reflectance = REFLECTANCE_MULT_BAND_X(0.00002)*DN + REFLECTANCE_ADD_BAND_X (-0.1)

    b). Reflectance with correction of sun angle = Reflectance/ Sin(Ɵ)

    Here Sin(Ɵ) = Sin(49.52284282) = 0.760664796730206

  • 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 generated in Step 02

  • Step 04: Generated a RGB composite using Red = band 4, Green = band 3 and Blue = band 2. (All bands derived at Step 03)

I am attaching the resultant image for comparison. Obviously, I missed something. Atmospherically adjusted Image should’ve been clearer. Its not even looking like an RGB image.

Also attaching the Metadata file, 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.

Can anyone tell me how I can get a correct atmospherically adjusted image?

enter image description here

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?

Metadata file
================================================================================
GROUP = L1_METADATA_FILE
  GROUP = METADATA_FILE_INFO
    ORIGIN = "Image courtesy of the U.S. Geological Survey"
    REQUEST_ID = "0501510272804_00036"
    LANDSAT_SCENE_ID = "LC81370442015300LGN00"
    FILE_DATE = 2015-10-27T08:52:24Z
    STATION_ID = "LGN"
    PROCESSING_SOFTWARE_VERSION = "LPGS_2.5.1"
  END_GROUP = METADATA_FILE_INFO
  GROUP = PRODUCT_METADATA
    DATA_TYPE = "L1T"
    ELEVATION_SOURCE = "GLS2000"
    OUTPUT_FORMAT = "GEOTIFF"
    SPACECRAFT_ID = "LANDSAT_8"
    SENSOR_ID = "OLI_TIRS"
    WRS_PATH = 137
    WRS_ROW = 44
    NADIR_OFFNADIR = "NADIR"
    TARGET_WRS_PATH = 137
    TARGET_WRS_ROW = 44
    DATE_ACQUIRED = 2015-10-27
    SCENE_CENTER_TIME = "04:24:55.0190611Z"
    CORNER_UL_LAT_PRODUCT = 24.15030
    CORNER_UL_LON_PRODUCT = 89.24071
    CORNER_UR_LAT_PRODUCT = 24.18946
    CORNER_UR_LON_PRODUCT = 91.51825
    CORNER_LL_LAT_PRODUCT = 22.01936
    CORNER_LL_LON_PRODUCT = 89.29959
    CORNER_LR_LAT_PRODUCT = 22.05469
    CORNER_LR_LON_PRODUCT = 91.54152
    CORNER_UL_PROJECTION_X_PRODUCT = 117900.000
    CORNER_UL_PROJECTION_Y_PRODUCT = 2676000.000
    CORNER_UR_PROJECTION_X_PRODUCT = 349500.000
    CORNER_UR_PROJECTION_Y_PRODUCT = 2676000.000
    CORNER_LL_PROJECTION_X_PRODUCT = 117900.000
    CORNER_LL_PROJECTION_Y_PRODUCT = 2439600.000
    CORNER_LR_PROJECTION_X_PRODUCT = 349500.000
    CORNER_LR_PROJECTION_Y_PRODUCT = 2439600.000
    PANCHROMATIC_LINES = 15761
    PANCHROMATIC_SAMPLES = 15441
    REFLECTIVE_LINES = 7881
    REFLECTIVE_SAMPLES = 7721
    THERMAL_LINES = 7881
    THERMAL_SAMPLES = 7721
    FILE_NAME_BAND_1 = "LC81370442015300LGN00_B1.TIF"
    FILE_NAME_BAND_2 = "LC81370442015300LGN00_B2.TIF"
    FILE_NAME_BAND_3 = "LC81370442015300LGN00_B3.TIF"
    FILE_NAME_BAND_4 = "LC81370442015300LGN00_B4.TIF"
    FILE_NAME_BAND_5 = "LC81370442015300LGN00_B5.TIF"
    FILE_NAME_BAND_6 = "LC81370442015300LGN00_B6.TIF"
    FILE_NAME_BAND_7 = "LC81370442015300LGN00_B7.TIF"
    FILE_NAME_BAND_8 = "LC81370442015300LGN00_B8.TIF"
    FILE_NAME_BAND_9 = "LC81370442015300LGN00_B9.TIF"
    FILE_NAME_BAND_10 = "LC81370442015300LGN00_B10.TIF"
    FILE_NAME_BAND_11 = "LC81370442015300LGN00_B11.TIF"
    FILE_NAME_BAND_QUALITY = "LC81370442015300LGN00_BQA.TIF"
    METADATA_FILE_NAME = "LC81370442015300LGN00_MTL.txt"
    BPF_NAME_OLI = "LO8BPF20151027040956_20151027054850.01"
    BPF_NAME_TIRS = "LT8BPF20151027040602_20151027054456.01"
    CPF_NAME = "L8CPF20151001_20151231.01"
    RLUT_FILE_NAME = "L8RLUT20150303_20431231v11.h5"
  END_GROUP = PRODUCT_METADATA
  GROUP = IMAGE_ATTRIBUTES
    CLOUD_COVER = 4.67
    CLOUD_COVER_LAND = 4.75
    IMAGE_QUALITY_OLI = 9
    IMAGE_QUALITY_TIRS = 9
    TIRS_SSM_POSITION_STATUS = "NOMINAL"
    ROLL_ANGLE = -0.001
    SUN_AZIMUTH = 150.12621205
    SUN_ELEVATION = 49.52284282
    EARTH_SUN_DISTANCE = 0.9939432
    GROUND_CONTROL_POINTS_VERSION = 2
    GROUND_CONTROL_POINTS_MODEL = 298
    GEOMETRIC_RMSE_MODEL = 6.823
    GEOMETRIC_RMSE_MODEL_Y = 4.812
    GEOMETRIC_RMSE_MODEL_X = 4.837
    GROUND_CONTROL_POINTS_VERIFY = 88
    GEOMETRIC_RMSE_VERIFY = 4.846
  END_GROUP = IMAGE_ATTRIBUTES
  GROUP = MIN_MAX_RADIANCE
    RADIANCE_MAXIMUM_BAND_1 = 769.35406
    RADIANCE_MINIMUM_BAND_1 = -63.53351
    RADIANCE_MAXIMUM_BAND_2 = 787.82794
    RADIANCE_MINIMUM_BAND_2 = -65.05909
    RADIANCE_MAXIMUM_BAND_3 = 725.97668
    RADIANCE_MINIMUM_BAND_3 = -59.95139
    RADIANCE_MAXIMUM_BAND_4 = 612.18445
    RADIANCE_MINIMUM_BAND_4 = -50.55439
    RADIANCE_MAXIMUM_BAND_5 = 374.62637
    RADIANCE_MINIMUM_BAND_5 = -30.93677
    RADIANCE_MAXIMUM_BAND_6 = 93.16617
    RADIANCE_MINIMUM_BAND_6 = -7.69369
    RADIANCE_MAXIMUM_BAND_7 = 31.40199
    RADIANCE_MINIMUM_BAND_7 = -2.59319
    RADIANCE_MAXIMUM_BAND_8 = 692.82434
    RADIANCE_MINIMUM_BAND_8 = -57.21366
    RADIANCE_MAXIMUM_BAND_9 = 146.41248
    RADIANCE_MINIMUM_BAND_9 = -12.09079
    RADIANCE_MAXIMUM_BAND_10 = 22.00180
    RADIANCE_MINIMUM_BAND_10 = 0.10033
    RADIANCE_MAXIMUM_BAND_11 = 22.00180
    RADIANCE_MINIMUM_BAND_11 = 0.10033
  END_GROUP = MIN_MAX_RADIANCE
  GROUP = MIN_MAX_REFLECTANCE
    REFLECTANCE_MAXIMUM_BAND_1 = 1.210700
    REFLECTANCE_MINIMUM_BAND_1 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_2 = 1.210700
    REFLECTANCE_MINIMUM_BAND_2 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_3 = 1.210700
    REFLECTANCE_MINIMUM_BAND_3 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_4 = 1.210700
    REFLECTANCE_MINIMUM_BAND_4 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_5 = 1.210700
    REFLECTANCE_MINIMUM_BAND_5 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_6 = 1.210700
    REFLECTANCE_MINIMUM_BAND_6 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_7 = 1.210700
    REFLECTANCE_MINIMUM_BAND_7 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_8 = 1.210700
    REFLECTANCE_MINIMUM_BAND_8 = -0.099980
    REFLECTANCE_MAXIMUM_BAND_9 = 1.210700
    REFLECTANCE_MINIMUM_BAND_9 = -0.099980
  END_GROUP = MIN_MAX_REFLECTANCE
  GROUP = MIN_MAX_PIXEL_VALUE
    QUANTIZE_CAL_MAX_BAND_1 = 65535
    QUANTIZE_CAL_MIN_BAND_1 = 1
    QUANTIZE_CAL_MAX_BAND_2 = 65535
    QUANTIZE_CAL_MIN_BAND_2 = 1
    QUANTIZE_CAL_MAX_BAND_3 = 65535
    QUANTIZE_CAL_MIN_BAND_3 = 1
    QUANTIZE_CAL_MAX_BAND_4 = 65535
    QUANTIZE_CAL_MIN_BAND_4 = 1
    QUANTIZE_CAL_MAX_BAND_5 = 65535
    QUANTIZE_CAL_MIN_BAND_5 = 1
    QUANTIZE_CAL_MAX_BAND_6 = 65535
    QUANTIZE_CAL_MIN_BAND_6 = 1
    QUANTIZE_CAL_MAX_BAND_7 = 65535
    QUANTIZE_CAL_MIN_BAND_7 = 1
    QUANTIZE_CAL_MAX_BAND_8 = 65535
    QUANTIZE_CAL_MIN_BAND_8 = 1
    QUANTIZE_CAL_MAX_BAND_9 = 65535
    QUANTIZE_CAL_MIN_BAND_9 = 1
    QUANTIZE_CAL_MAX_BAND_10 = 65535
    QUANTIZE_CAL_MIN_BAND_10 = 1
    QUANTIZE_CAL_MAX_BAND_11 = 65535
    QUANTIZE_CAL_MIN_BAND_11 = 1
  END_GROUP = MIN_MAX_PIXEL_VALUE
  GROUP = RADIOMETRIC_RESCALING
    RADIANCE_MULT_BAND_1 = 1.2709E-02
    RADIANCE_MULT_BAND_2 = 1.3014E-02
    RADIANCE_MULT_BAND_3 = 1.1993E-02
    RADIANCE_MULT_BAND_4 = 1.0113E-02
    RADIANCE_MULT_BAND_5 = 6.1886E-03
    RADIANCE_MULT_BAND_6 = 1.5390E-03
    RADIANCE_MULT_BAND_7 = 5.1874E-04
    RADIANCE_MULT_BAND_8 = 1.1445E-02
    RADIANCE_MULT_BAND_9 = 2.4186E-03
    RADIANCE_MULT_BAND_10 = 3.3420E-04
    RADIANCE_MULT_BAND_11 = 3.3420E-04
    RADIANCE_ADD_BAND_1 = -63.54622
    RADIANCE_ADD_BAND_2 = -65.07210
    RADIANCE_ADD_BAND_3 = -59.96339
    RADIANCE_ADD_BAND_4 = -50.56450
    RADIANCE_ADD_BAND_5 = -30.94296
    RADIANCE_ADD_BAND_6 = -7.69523
    RADIANCE_ADD_BAND_7 = -2.59370
    RADIANCE_ADD_BAND_8 = -57.22510
    RADIANCE_ADD_BAND_9 = -12.09321
    RADIANCE_ADD_BAND_10 = 0.10000
    RADIANCE_ADD_BAND_11 = 0.10000
    REFLECTANCE_MULT_BAND_1 = 2.0000E-05
    REFLECTANCE_MULT_BAND_2 = 2.0000E-05
    REFLECTANCE_MULT_BAND_3 = 2.0000E-05
    REFLECTANCE_MULT_BAND_4 = 2.0000E-05
    REFLECTANCE_MULT_BAND_5 = 2.0000E-05
    REFLECTANCE_MULT_BAND_6 = 2.0000E-05
    REFLECTANCE_MULT_BAND_7 = 2.0000E-05
    REFLECTANCE_MULT_BAND_8 = 2.0000E-05
    REFLECTANCE_MULT_BAND_9 = 2.0000E-05
    REFLECTANCE_ADD_BAND_1 = -0.100000
    REFLECTANCE_ADD_BAND_2 = -0.100000
    REFLECTANCE_ADD_BAND_3 = -0.100000
    REFLECTANCE_ADD_BAND_4 = -0.100000
    REFLECTANCE_ADD_BAND_5 = -0.100000
    REFLECTANCE_ADD_BAND_6 = -0.100000
    REFLECTANCE_ADD_BAND_7 = -0.100000
    REFLECTANCE_ADD_BAND_8 = -0.100000
    REFLECTANCE_ADD_BAND_9 = -0.100000
  END_GROUP = RADIOMETRIC_RESCALING
  GROUP = TIRS_THERMAL_CONSTANTS
    K1_CONSTANT_BAND_10 = 774.8853
    K1_CONSTANT_BAND_11 = 480.8883
    K2_CONSTANT_BAND_10 = 1321.0789
    K2_CONSTANT_BAND_11 = 1201.1442
  END_GROUP = TIRS_THERMAL_CONSTANTS
  GROUP = PROJECTION_PARAMETERS
    MAP_PROJECTION = "UTM"
    DATUM = "WGS84"
    ELLIPSOID = "WGS84"
    UTM_ZONE = 46
    GRID_CELL_SIZE_PANCHROMATIC = 15.00
    GRID_CELL_SIZE_REFLECTIVE = 30.00
    GRID_CELL_SIZE_THERMAL = 30.00
    ORIENTATION = "NORTH_UP"
    RESAMPLING_OPTION = "CUBIC_CONVOLUTION"
  END_GROUP = PROJECTION_PARAMETERS
END_GROUP = L1_METADATA_FILE
END

Command Output Log
================================================================================
Atmospheric Correction Band 4

(Fri Nov 13 23:54:00 2015)                                                      
i.atcorr -r --verbose input=TOAR_B4@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@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@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@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@TOAR green=ATM_B3@TOAR blue=ATM_B2@TOAR pan=ATM_B8@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@TOAR> to group
Adding raster map <PAN_RGB_blue@TOAR> to group
Adding raster map <PAN_RGB_green@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@TOAR green=PAN_RGB_green@TOAR blue=PAN_RGB_blue@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)       

Sample Control File for Band 2
================================================================================
18
10 27 4.41 90.373 23.113
1
3
0
0.55
-0.004
-1000
116
Improve this question
4
  • 3
    A bunch of questions: (a) Why do you think that the image is supposed to be clearer? (b) Have you tried stretching the atmospherically corrected image? (c) What value ranges does your atmospherically corrected image have? Lastly, pansharpening after atmospheric correction is risky, and you will loose some of the spectral fidelity with that operation, meaning you may end up with negative / nonsense values.
    – Mikkel Lydholm Rasmussen
    Nov 16, 2015 at 12:39
  • a). Because of hazy Bands, difficult to distinguish between land covers. Hence looking for dehazing. But , the extension is no longer available in Grass. Further literature review suggests atmospheric correction a viable alternative. Grass reference suggests it as a pre-processing step. grasswiki.osgeo.org/wiki/LANDSAT also cpi.com/products/act.html b). Not yet. c).B8 :min = 1.501154e-005 max = 3.678026 B4 :min = 1.149623e-006 max = 2.351371 B3 :min = 7.561963e-006 max = 4.233557 B2 :min = 1.508958e-005 max = 1.797155 d.detail is preferred. Any alternative mthd? Ty.
    – ıat7b
    Nov 16, 2015 at 15:14
  • 1
    Atmospheric correction, by itself, will not make your image clearer. Currently, you are not taking any information from the image, so the atmospheric correction module doesn't know which parts are hazy and which parts are clear. As such, the atmospheric correction is the same for every pixel in your image. Furthermore, the min-max values from your image indicates to me that something went wrong in your correction. The minimum is okay, but the maximum is very high. 6S based atmospheric correction should give you values between 0 and 1, with 1 being unrealistically high.
    – Mikkel Lydholm Rasmussen
    Nov 16, 2015 at 15:52
  • Thanks. I'll review it further and incorporate your observations in my approach.
    – ıat7b
    Nov 16, 2015 at 16:01

1 Answer 1

Reset to default
1

I would suggest taking one step at a time.

First try the i.landsat.toar module and compare the values with your results to your step 1.

Second you need to be careful with the i.pansharpen module as I think it only accepts 8 bit data so the float data produced from atmospheric correction is going to give you issues.

If you want to pan-sharpen atmospherically corrected data try using mapcalc (make sure your region settings have resolution 15m x 15m). The formulas are written in the i.pansharpen docs and available here: http://www.sensorsportal.com/HTML/DIGEST/august_2014/Vol_177/P_RP_0183.pdf

So check your individual bands with a greyscale color-ramp then if they all look good have a go at composite.

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