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NAME

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

KEYWORDS

raster, algebra

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

Table of contents

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:
  1. define position: set bit(s) to 1 which shall match, then convert this position pattern to integer, set pattern= parameter with that integer value
  2. 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 pixels in the input satellite image using r.mapcalc (OR and NOT operators).

EXAMPLE

  1. Define position:
        xx xx 1x xx
        binary: 1000 -> integer: 8 -> pattern=8
    
  2. 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 arbitrary (0/1), then assume 0 value
    

SEE ALSO

i.modis.qc, r.mapcalc

AUTHORS

Radim Blazek, Markus Neteler

SOURCE CODE

Available at: r.bitpattern source code (history)

Latest change: Wednesday Feb 02 21:46:15 2022 in commit: 2e3dcb5eafe36d640aa68585be0192f07ca1eabb


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© 2003-2022 GRASS Development Team, GRASS GIS 8.2.0 Reference Manual