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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 pixel 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 arbitray (0/1), then assume 0 value
    

SEE ALSO

i.modis.qc, r.mapcalc

AUTHORS

Radim Blazek, Markus Neteler

Last changed: $Date: 2013-10-02 22:30:48 +0200 (Wed, 02 Oct 2013) $

SOURCE CODE

Available at: r.bitpattern source code (history)


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© 2003-2017 GRASS Development Team, GRASS GIS 7.2.3svn Reference Manual