Tool Cloud Shadow Detection

This tool derives cloud shadows from detected clouds based on their spectral characteristics as well as terrain, sun position and expected cloud height. The initial cloud mask can be created by the tool "Cloud Detection".

References

Irish, R.R. (2000): Landsat 7 Automatic Cloud Cover Assessment. In: Shen, S.S., Descour, M.R. [Eds.]: Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI. Proceedings of SPIE, 4049: 348-355. doi:10.1117/12.410358.
Tizado, E.J. (2010): GRASS GIS i.landsat.acca. E.J. Tizado's implementation of the ACCA algorithm as proposed by Irish (2000), Irish et al. (2006). Source Code.

Author: J.Spitzmüller, O.Conrad (c) 2023
Menu: Imagery|Feature Extraction

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Clouds	Grid, input	`CLOUDS`	-	-
	Candidates	Grid, input	`CAND_GRID_IN`	-	-
	Elevation (*)	Grid, input, optional	`DEM`	-	-
	Green	Grid, input	`BAND_GREEN`	-	-
	Red	Grid, input	`BAND_RED`	-	-
	Near Infrared	Grid, input	`BAND_NIR`	-	-
	Shortwave Infrared	Grid, input	`BAND_SWIR`	-	-
	Thermal (*)	Grid, input, optional	`BAND_THERMAL`	-	-
	Brightness Bands	Grid list, input	`BANDS_BRIGHTNESS`	-	-
Output	Cloud Number (*)	Grid, output, optional	`CLOUD_ID`	-	-
	Candidates (*)	Grid, output, optional	`CAND_GRID_OUT`	-	-
	Shadows	Grid, output	`SHADOWS`	-	-
	Cloud Info	Table, output	`CLOUD_INFO`	-	-
Options	Grid System	Grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Grid System	Grid system	`BANDS_SWIR`	-	-
	Grid System	Grid system	`BANDS_THERMAL`	-	-
	Output	Choice	`OUTPUT`	-	Available Choices: [0] visible shadow [1] full shadow [2] shadow and clouds Default: 2
	Value	Floating point	`CAND_GRID_VALUE`	-	Default: 0.000000
	Unit	Choice	`THERMAL_UNIT`	-	Available Choices: [0] Kelvin [1] Celsius Default: 0
	Candidates	Choice	`CANDIDATES`	-	Available Choices: [0] all cells of candidates grid that are not no-data [1] all cells of candidates grid with a specified value [2] average brightness threshold [3] Irish [4] Irish modified by Tizado Default: 0
	Brightness Threshold	Floating point	`BRIGHTNESS`	-	Minimum: 0.000000 Maximum: 1.000000 Default: 0.050000
	Processing	Choice	`PROCESSING`	-	Available Choices: [0] all clouds at once [1] cloud by cloud Default: 0
	Azimuth	Floating point	`SUN_AZIMUTH`	Direction of sun clockwise from North [degree].	Minimum: 0.000000 Maximum: 360.000000 Default: -180.000000
	Height	Floating point	`SUN_HEIGHT`	Height of sun above horizon [degree].	Minimum: 0.000000 Maximum: 90.000000 Default: 45.000000
	Cloud Height	Value range	`CLOUD_HEIGHT`	The range of cloud height above ground to be tested.	-
(*) optional

Command-line

Usage: saga_cmd imagery_tools 21 [-CLOUDS <str>] [-CAND_GRID_IN <str>] [-DEM <str>] [-CLOUD_ID <str>] [-CAND_GRID_OUT <str>] [-SHADOWS <str>] [-CLOUD_INFO <str>] [-BAND_GREEN <str>] [-BAND_RED <str>] [-BAND_NIR <str>] [-BAND_SWIR <str>] [-BAND_THERMAL <str>] [-BANDS_BRIGHTNESS <str>] [-OUTPUT <str>] [-CAND_GRID_VALUE <double>] [-THERMAL_UNIT <str>] [-CANDIDATES <str>] [-BRIGHTNESS <double>] [-PROCESSING <str>] [-SUN_AZIMUTH <double>] [-SUN_HEIGHT <double>] [-CLOUD_HEIGHT_MIN <double>] [-CLOUD_HEIGHT_MAX <double>]
  -CLOUDS:<str>             	Clouds
	Grid, input
  -CAND_GRID_IN:<str>       	Candidates
	Grid, input
  -DEM:<str>                	Elevation
	Grid, input, optional
  -CLOUD_ID:<str>           	Cloud Number
	Grid, output, optional
  -CAND_GRID_OUT:<str>      	Candidates
	Grid, output, optional
  -SHADOWS:<str>            	Shadows
	Grid, output
  -CLOUD_INFO:<str>         	Cloud Info
	Table, output
  -BAND_GREEN:<str>         	Green
	Grid, input
  -BAND_RED:<str>           	Red
	Grid, input
  -BAND_NIR:<str>           	Near Infrared
	Grid, input
  -BAND_SWIR:<str>          	Shortwave Infrared
	Grid, input
  -BAND_THERMAL:<str>       	Thermal
	Grid, input, optional
  -BANDS_BRIGHTNESS:<str>   	Brightness Bands
	Grid list, input
  -OUTPUT:<str>             	Output
	Choice
	Available Choices:
	[0] visible shadow
	[1] full shadow
	[2] shadow and clouds
	Default: 2
  -CAND_GRID_VALUE:<double> 	Value
	Floating point
	Default: 0.000000
  -THERMAL_UNIT:<str>       	Unit
	Choice
	Available Choices:
	[0] Kelvin
	[1] Celsius
	Default: 0
  -CANDIDATES:<str>         	Candidates
	Choice
	Available Choices:
	[0] all cells of candidates grid that are not no-data
	[1] all cells of candidates grid with a specified value
	[2] average brightness threshold
	[3] Irish
	[4] Irish modified by Tizado
	Default: 0
  -BRIGHTNESS:<double>      	Brightness Threshold
	Floating point
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.050000
  -PROCESSING:<str>         	Processing
	Choice
	Available Choices:
	[0] all clouds at once
	[1] cloud by cloud
	Default: 0
  -SUN_AZIMUTH:<double>     	Azimuth
	Floating point
	Minimum: 0.000000
	Maximum: 360.000000
	Default: -180.000000
  -SUN_HEIGHT:<double>      	Height
	Floating point
	Minimum: 0.000000
	Maximum: 90.000000
	Default: 45.000000
  -CLOUD_HEIGHT_MIN:<double>	Cloud Height
	Value range
  -CLOUD_HEIGHT_MAX:<double>	Cloud Height
	Value range