i.wi - GRASS GIS manual

NAME

i.wi - Calculates different types of water indices.

KEYWORDS

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)