r.fusion - GRASS GIS manual

Note: This document is for an older version of GRASS GIS that has been discontinued. You should upgrade, and read the current manual page.

NAME

r.fusion - image fusion, generalized pan-sharpening

KEYWORDS

raster, imagery, fusion, sharpen

SYNOPSIS

r.fusion

r.fusion --help

r.fusion [-r] input=name highres=name [method=string] output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-r: Restrict output value range to input value range; Recommended for imagery with a defined valid value range, e.g. [0, 255]
--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:

input=name [required]: Low-resolution raster to be enhanced
highres=name [required]: High-resolution raster with spatial detail
method=string: Solution method: Finite Diff. or Superpos. of analytical sol'ns; Options: difference, proportion; Default: difference
output=name [required]: Name for output raster map

DESCRIPTION
NOTES
SEE ALSO
AUTHOR

DESCRIPTION

r.fusion enhances the resolution of a raster map by using spatial detail of a high-resolution map. The actual values in the resultant output map correspond to the input map while the spatial detail corresponds to the high-resolution map. The effect is similar to pan-sharpening, but the method can be applied more generally, not only to imagery but also to climatological data such as temperature or precipitation.

NOTES

Two different methods are available with the method option: difference and proportion.

The difference method uses the formula

A - B + B = A

more specifically

highres(A_lowres - B_lowres) + B_highres = A_highres

where highres() is a function to interpolate the differences. Here, r.resamp.filter is used for interpolation.

The proportion method is suitable for e.g. precipitation where zero precipition must stay zero precipition, and uses the formula

A / B * B = A

more specifically

highres(A_lowres / B_lowres) * B_highres = A_highres

Again, highres() is a function to interpolate the proportions, and r.resamp.filter is used for interpolation. For the proportion method, all values in the high-resolution B map must be > 0.

AUTHOR

Markus Metz, mundialis

SOURCE CODE

Available at: r.fusion source code (history)

Latest change: Saturday Dec 14 22:40:49 2024 in commit: 9ee101add7145f5ea84ff96a91d2e0e0a8fad3b9