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NAME
r.bitpattern - Compares bit patterns with a raster map.
KEYWORDS
raster, map algebra
SYNOPSIS
r.bitpattern
r.bitpattern help
r.bitpattern [-q] input=name output=name pattern=integer patval=integer [--overwrite] [--verbose] [--quiet]
Flags:
- -q
- Quiet
- --overwrite
- Allow output files to overwrite existing files
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- input=name
- Name of input raster map
- output=name
- Name for output raster map
- pattern=integer
- Bit pattern position(s)
- patval=integer
- Bit pattern value
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
SEE ALSO
r.mapcalc
AUTHORS
Radim Blazek, Markus Neteler
Last changed: $Date: 2008-05-16 12:09:06 -0700 (Fri, 16 May 2008) $
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