GRASS GIS manual: r.reclass.area

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.4, available here.
Updated manual page: here

NAME

r.reclass.area - Reclasses a raster map greater or less than user specified area size (in hectares).

KEYWORDS

raster, statistics, aggregation

SYNOPSIS

r.reclass.area

r.reclass.area --help

r.reclass.area [-cd] input=name output=name value=float mode=string [method=string] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-c: Input map is clumped
-d: Clumps including diagonal neighbors
--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
value=float [required]: Value option that sets the area size limit (in hectares)
mode=string [required]: Lesser or greater than specified value; Options: lesser, greater
method=string: Method used for reclassification; Options: reclass, rmarea; Default: reclass

DESCRIPTION
EXAMPLES
SEE ALSO
AUTHORS

DESCRIPTION

r.reclass.area reclasses a raster map greater or less than a user specified area size (in hectares).

If the -c flag is used, r.reclass.area will skip the creation of a clumped raster and assume that the input raster is already clumped.

EXAMPLES

In this example, the ZIP code map in the North Carolina sample dataset location is filtered for large areas (removing smaller areas from the map):

g.region raster=zipcodes -p
r.report zipcodes unit=h

# extract only areas greater than 2000 ha, NULL otherwise:
r.reclass.area input=zipcodes output=zipcodes_larger2000ha \
               mode=greater value=2000

r.report zipcodes_larger2000ha unit=h

In this example, the ZIP code map in the North Carolina sample dataset location is filtered for smaller areas which are substituted with the value of the respective adjacent area with largest shared boundary:

# reclass by substitutional removing of areas minor of 1000 ha
r.reclass.area input=zipcodes output=zipcodes_minor1000ha \
               mode=lesser value=1000 method=rmarea