GRASS GIS manual: v.buffer

Note: This document is for an older version of GRASS GIS that is outdated. You should upgrade, and read the current manual page.

NAME

v.buffer - Creates a buffer around features of given type (areas must contain centroid).

KEYWORDS

vector, buffer

SYNOPSIS

v.buffer
v.buffer help
v.buffer [-sc] input=name output=name [type=string[,string,...]] [layer=integer] [distance=float] [minordistance=float] [angle=float] [bufcolumn=name] [scale=float] [tolerance=float] [debug=string] [buffer=float] [--overwrite] [--verbose] [--quiet]

Flags:

-s: Make outside corners straight
-c: Don't make caps at the ends of polylines
--overwrite: Allow output files to overwrite existing files
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

input=name: Name of input vector map
output=name: Name for output vector map
type=string[,string,...]: Feature type; Options: point,line,boundary,centroid,area; Default: point,line,area
layer=integer: Layer number; A single vector map can be connected to multiple database tables. This number determines which table to use.; Default: 1
distance=float: Buffer distance along major axis in map units
minordistance=float: Buffer distance along minor axis in map units
angle=float: Angle of major axis in degrees; Default: 0
bufcolumn=name: Name of column to use for buffer distances
scale=float: Scaling factor for attribute column values; Default: 1.0
tolerance=float: Maximum distance between theoretical arc and polygon segments as multiple of buffer; Default: 0.01
debug=string: This does nothing. It is retained for backwards compatibility
buffer=float: This is an alias to the distance option. It is retained for backwards compatibility; Buffer distance in map units

DESCRIPTION

v.buffer creates a buffer around features of given type, which have a category in the given layer. The tolerance controls the number of vector segments being generated (the smaller the value, the more vector segments are generated).

NOTES

Attributes are not transferred due to potential buffer overlap, which cannot be resolved automatically.

EXAMPLES

All examples are based on the North Carolina sample dataset.

Buffer around input lines

v.buffer input=roadsmajor output=roadsmajor_buffer type=line distance=100

Buffer of 100m along the "roadsmajor" lines (map subset, original center line shown in black)

Circles around input points

v.buffer input=hospitals output=hospitals_circled type=point distance=1000

Overlapping circles around input points with attribute transfer

v.buffer input=hospitals output=circles type=point distance=2000
# change original points to centroids: 
v.type in=hospitals out=hospital_centroids type=point,centroid 
# patch circles and centroids: 
v.patch in=hospital_centroids,circles out=circles_db 
# attach attributes, either use db.copy or link to the original table: 
v.db.connect map=circles_db table=hospitals layer=1 key=cat driver=dbf \
     database='$GISDBASE/$LOCATION_NAME/$MAPSET/dbf'

Buffer of 2000m around the "hospitals" points (map subset, original points shown in black, new area centroids in red)

Buffer around input areas

v.buffer input=lakes output=lakes_buffer type=area distance=100

Buffer of 100m around the "lakes" polygons (map subset, original areas shown in black)

AUTHORS

Radim Blazek
Rewritten by Rosen Matev (with support through the Google Summer of Code program 2008)

Last changed: $Date: 2014-03-31 14:14:21 -0700 (Mon, 31 Mar 2014) $

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