i.wi - GRASS GIS manual

Note: This addon document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade your GRASS GIS installation, and read the current addon manual page.

NAME

i.wi - Calculates different types of water indices.

KEYWORDS

imagery, water, index, biophysical

SYNOPSIS

i.wi

i.wi --help

i.wi winame=type [blue=name] [green=name] [red=name] [nir=name] [band5=name] [band7=name] output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

winame=type [required]: Type of water index; Options: 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

DESCRIPTION
NOTES
TODO
REFERENCES
SEE ALSO
AUTHOR

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. http://dx.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. http://dx.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. http://dx.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, http://dx.doi.org/10.1016/j.rse.2015.12.055.

AUTHOR

SOURCE CODE

Available at: i.wi source code (history)

Latest change: Mon Jun 28 07:54:09 2021 in commit: 1cfc0af029a35a5d6c7dae5ca7204d0eb85dbc55