---
name: "r.bitpattern"
section: "1grass"
platform: "linux"
package: "grass-doc"
version: "6.4.4-1"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/r.bitpattern"
---

# r.bitpattern(1grass)

Compares bit patterns with a raster map.

## 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:

- **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

*r.mapcalc*

## AUTHORS

Radim Blazek, Markus Neteler

*Last changed: $Date: 2008-05-16 21:09:06 +0200 (Fri, 16 May 2008) $*

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