Tool NameCloud Shadow Detection
Tool ID21
Library IDimagery_tools
Version1.0
Author(s)J.Spitzmüller, O.Conrad (c) 2023

Description

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


Parameters

NameTypeIdentifierDescriptionConstraints
Input
Cloudsgrid, inputCLOUDS
Candidatesgrid, inputCAND_GRID_IN
Elevationgrid, input, optionalDEM
Greengrid, inputBAND_GREEN
Redgrid, inputBAND_RED
Near Infraredgrid, inputBAND_NIR
Shortwave Infraredgrid, inputBAND_SWIR
Thermalgrid, input, optionalBAND_THERMAL
Brightness Bandsgrid list, inputBANDS_BRIGHTNESS
Output
Cloud Numbergrid, output, optionalCLOUD_ID
Candidatesgrid, output, optionalCAND_GRID_OUT
Shadowsgrid, outputSHADOWS
Cloud Infotable, outputCLOUD_INFO
Options
OutputchoiceOUTPUTAvailable Choices:
[0] visible shadow
[1] full shadow
[2] shadow and clouds
Default: 2
Valuefloating point numberCAND_GRID_VALUEDefault: 0.000000
UnitchoiceTHERMAL_UNITAvailable Choices:
[0] Kelvin
[1] Celsius
Default: 0
CandidateschoiceCANDIDATESAvailable 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 Thresholdfloating point numberBRIGHTNESSMinimum: 0.000000
Maximum: 1.000000
Default: 0.050000
ProcessingchoicePROCESSINGAvailable Choices:
[0] all clouds at once
[1] cloud by cloud
Default: 0
Azimuthfloating point numberSUN_AZIMUTHDirection of sun clockwise from North [degree].Minimum: 0.000000
Maximum: 360.000000
Default: -180.000000
Heightfloating point numberSUN_HEIGHTHeight of sun above horizon [degree].Minimum: 0.000000
Maximum: 90.000000
Default: 45.000000
Cloud Heightvalue rangeCLOUD_HEIGHTThe range of cloud height above ground to be tested.