r.bitpattern - GRASS GIS manual

NAME

r.bitpattern - Compares bit patterns with a raster map.

KEYWORDS

SYNOPSIS

r.bitpattern

r.bitpattern --help

r.bitpattern input=name output=name pattern=integer patval=integer [--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:

input=name [required]: Name of input raster map
output=name [required]: Name for output raster map
pattern=integer [required]: Bit pattern position(s)
patval=integer [required]: Bit pattern value

DESCRIPTION
EXAMPLE
SEE ALSO
AUTHORS

DESCRIPTION

r.bitpattern performs bit pattern comparisons. The module can be used to pixelwise verify a satellite image for low quality pixels if a Quality Control Bit Index map is provided (e.g. as for MODIS sensor maps). The functionality is two-fold:

define position: set bit(s) to 1 which shall match, then convert this position pattern to integer, set pattern= parameter with that integer value
define pattern *value* which should be in that position: first bit pattern of value, convert to integer, set patval= parameter

If several bitpatterns have to be tested, the resulting maps can be used to exclude low quality pixel in the input satellite image using r.mapcalc (OR and NOT operators).

EXAMPLE

define position:

	xx xx 1x xx
	binary: 1000 -> integer: 8 -> pattern=8

define value:

        Ex.: we want to check for 0 in that position
	xx xx 0x xx
	binary: 0000 -> integer: 0 -> patval=0
        if value can be arbitray (0/1), then assume 0 value

AUTHORS

Radim Blazek, Markus Neteler

SOURCE CODE

Available at: r.bitpattern source code (history)