r.buffer.lowmem.1grass man page

r.buffer.lowmem — Creates a raster map showing buffer zones surrounding cells that contain non-NULL category values.
This is the low-memory alternative to the classic r.buffer module.

Keywords

raster, buffer

Synopsis

r.buffer.lowmem
r.buffer.lowmem --help
r.buffer.lowmem [-z] input=name output=name distances=float[,float,...]  [units=string]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

Flags

-z

Ignore zero (0) data cells instead of NULL cells

--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

distances=float[,float,...] [required]

Distance zone(s)

units=string

Units of distance
Options: meters, kilometers, feet, miles, nautmiles
Default: meters

Description

r.buffer.lowmem creates a new raster map showing buffer (a.k.a. "distance" or "proximity") zones around all cells that contain non-NULL category values in an existing raster map. The distances of buffer zones from cells with non-zero category values are user-chosen.

This is the low-memory alternative to the classic r.buffer module. It is much slower than the classic version, but will run on massive raster maps without using a lot of RAM. If your raster map is larger than 32000x32000 cells on a system with 1 GB of RAM, or larger than 90000x90000 cells on a system with 8 GB of RAM, consider using this module.

For more info see manual of r.buffer.

Example

In the following example, the buffer zones would be (in the default units of meters): 0-100, 101-200, 201-300, 301-400 and 401-500.

r.buffer.lowmem input=roads output=roads.buf distances=100,200,300,400,500

Result:

r.category input=roads.buf
      1       distances calculated from these locations
      2       0-100 meters
      3       100-200 meters
      4       200-300 meters
      5       300-400 meters
      6       400-500 meters

See Also

g.region, r.buffer, r.cost, r.grow.distance, r.mapcalc, r.reclass, v.buffer

Authors

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
James Westervelt, U.S. Army Construction Engineering Research Laboratory
Low-memory Python version by Glynn Clements

Last changed: $Date: 2013-01-04 07:21:51 -0800 (Fri, 04 Jan 2013) $

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