r.bitpattern1grass
Compares bit patterns with a raster map.
Usage
r.bitpattern
r.bitpattern help
r.bitpattern [-q]
input=name
output=name
pattern=integer
patval=integer
[--overwrite]
[--verbose]
[--quiet]
Keywords
raster, map algebra
Overview
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).
Examples
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
Releases
4 releases since Debian 5.0 (Lenny); the text changed 3 times.