i.wi
Calculates different types of water indices.
i.wi winame=type [blue=name] [green=name] [red=name] [nir=name] [band5=name] [band7=name] output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]
Example:
i.wi winame=lswi output=name
grass.script.run_command("i.wi", winame="lswi", blue=None, green=None, red=None, nir=None, band5=None, band7=None, output, overwrite=None, verbose=None, quiet=None, superquiet=None)
Example:
gs.run_command("i.wi", winame="lswi", output="name")
grass.tools.Tools.i_wi(winame="lswi", blue=None, green=None, red=None, nir=None, band5=None, band7=None, output, overwrite=None, verbose=None, quiet=None, superquiet=None)
Example:
tools = Tools()
tools.i_wi(winame="lswi", output="name")
This grass.tools API is experimental in version 8.5 and expected to be stable in version 8.6.
Parameters
winame=type [required]
Type of water index
Allowed values: awei_ns, awei_s, lswi, ndwi_mf, ndwi_x, tcw, wi
Default: lswi
awei_ns: Automated Water Extraction Index - No Shadow
awei_s: Automated Water Extraction Index - Shadow
lswi: Land Soil Water Index
ndwi_mf: Normalized Difference Water Index - Mc Feeters
ndwi_x: Normalized Difference Water Index - Xu
tcw: Tasseled Cap Water
wi: Water Index
blue=name
Name of input blue channel surface reflectance map
Range: [0.0;1.0]
green=name
Name of input green channel surface reflectance map
Range: [0.0;1.0]
red=name
Name of input red channel surface reflectance map
Range: [0.0;1.0]
nir=name
Name of input nir channel surface reflectance map
Range: [0.0;1.0]
band5=name
Name of input 5th channel surface reflectance map
Range: [0.0;1.0]
band7=name
Name of input 7th channel surface reflectance map
Range: [0.0;1.0]
output=name [required]
Name of the output wi layer
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--qq
Very quiet module output
--ui
Force launching GUI dialog
winame : str, required
Type of water index
Used as: type
Allowed values: awei_ns, awei_s, lswi, ndwi_mf, ndwi_x, tcw, wi
awei_ns: Automated Water Extraction Index - No Shadow
awei_s: Automated Water Extraction Index - Shadow
lswi: Land Soil Water Index
ndwi_mf: Normalized Difference Water Index - Mc Feeters
ndwi_x: Normalized Difference Water Index - Xu
tcw: Tasseled Cap Water
wi: Water Index
Default: lswi
blue : str, optional
Name of input blue channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
green : str, optional
Name of input green channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
red : str, optional
Name of input red channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
nir : str, optional
Name of input nir channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
band5 : str, optional
Name of input 5th channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
band7 : str, optional
Name of input 7th channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
output : str, required
Name of the output wi layer
Used as: output, raster, name
overwrite : bool, optional
Allow output files to overwrite existing files
Default: None
verbose : bool, optional
Verbose module output
Default: None
quiet : bool, optional
Quiet module output
Default: None
superquiet : bool, optional
Very quiet module output
Default: None
winame : str, required
Type of water index
Used as: type
Allowed values: awei_ns, awei_s, lswi, ndwi_mf, ndwi_x, tcw, wi
awei_ns: Automated Water Extraction Index - No Shadow
awei_s: Automated Water Extraction Index - Shadow
lswi: Land Soil Water Index
ndwi_mf: Normalized Difference Water Index - Mc Feeters
ndwi_x: Normalized Difference Water Index - Xu
tcw: Tasseled Cap Water
wi: Water Index
Default: lswi
blue : str | np.ndarray, optional
Name of input blue channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
green : str | np.ndarray, optional
Name of input green channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
red : str | np.ndarray, optional
Name of input red channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
nir : str | np.ndarray, optional
Name of input nir channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
band5 : str | np.ndarray, optional
Name of input 5th channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
band7 : str | np.ndarray, optional
Name of input 7th channel surface reflectance map
Range: [0.0;1.0]
Used as: input, raster, name
output : str | type(np.ndarray) | type(np.array) | type(gs.array.array), required
Name of the output wi layer
Used as: output, raster, name
overwrite : bool, optional
Allow output files to overwrite existing files
Default: None
verbose : bool, optional
Verbose module output
Default: None
quiet : bool, optional
Quiet module output
Default: None
superquiet : bool, optional
Very quiet module output
Default: None
Returns:
result : grass.tools.support.ToolResult | np.ndarray | tuple[np.ndarray] | None
If the tool produces text as standard output, a ToolResult object will be returned. Otherwise, None
will be returned. If an array type (e.g., np.ndarray) is used for one of the raster outputs, the result will be an array and will have the shape corresponding to the computational region. If an array type is used for more than one raster output, the result will be a tuple of arrays.
DESCRIPTION
i.wi calculates water indices based on biophysical parameters.
- AWEI: Automated Water Extraction Index (2 versions: no shadow or shadow
- LSWI: Land Surface Water Index
- NDWI: Normalized Difference Water Index (2 versions: McFeeters or Xu)
- TCW: Tasseled Cap Water
- WI: Water Index
NOTES
Requirements (as of Landsat 5TM bands)
- awei_noshadow needs greenchan, nirchan, chan5chan
- awei_shadow needs bluechan, greenchan, nirchan, chan5chan, chan7chan
- ls_wi needs nirchan, chan7chan
- ndwi_mcfeeters needs greenchan, nirchan
- ndwi_xu needs greenchan, chan5chan
- tcw needs bluechan, greenchan, redchan, nirchan, chan5chan, chan7chan
- wi needs greenchan, redchan, nirchan, chan5chan, chan7chan
TODO
Find other water indices and add them.
REFERENCES
AWEI: Automated Water Extraction Index
Feyisa, G.L., Meilby, H., Fensholt, R., Proud, S.R. (2014). Automated
Water Extraction Index: A new technique for surface water mapping using
Landsat imagery. Remote Sensing of Environment, 140, 23-35.
https://doi.org/10.1016/j.rse.2013.08.029.
LSWI: Land Surface Water Index
a kind of Normalized Difference Water Index Xiao X., Boles S., Frolking
S., Salas W., Moore B., Li C., et al. (2002) Landscape-scale
characterization of cropland in China using vegetation and Landsat TM
images. International Journal of Remote Sensing, 23:3579-3594.
NDWI McFeeters
McFeeters, S.K. (1996). The use of the Normalized Difference Water Index
(NDWI) in the delineation of open water features. International Journal
of Remote Sensing, 17, 1425-1432.
https://doi.org/10.1080/01431169608948714.
NDWI Xu
Xu, H. (2006). Modification of normalised difference water index (NDWI)
to enhance open water features in remotely sensed imagery. International
Journal of Remote Sensing, 27, 3025-3033.
https://doi.org/10.1080/01431160600589179.
TCW
Crist, E.P. (1985). A TM tasseled cap equivalent transformation for
reflectance factor data. Remote Sensing of Environment, 17, 301-306.
WI
Fisher, A., Flood, N., Danaher, T. (2016). Comparing Landsat water index
methods for automated water classification in eastern Australia. Remote
Sensing of Environment, 175, 167-182. ISSN 0034-4257,
https://doi.org/10.1016/j.rse.2015.12.055.
SEE ALSO
AUTHOR
Yann Chemin
SOURCE CODE
Available at: i.wi source code
(history)
Latest change: Friday Feb 21 12:27:42 2025 in commit 8fce680