Flags:¶

-s

Make outside corners straight

-c

Do not make caps at the ends of polylines

-t

Transfer categories and attributes

--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 vector map
Or data source for direct OGR access

layer=string

Layer number or name (’-1’ for all layers)
A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
Default: -1

cats=range

Category values
Example: 1,3,7-9,13

where=sql_query

WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and population >= 10000

type=string[,string,...]

Input feature type
Options: point, line, boundary, centroid, area
Default: point,line,area

output=name [required]

Name for output vector map

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

column=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)

Corner settings¶

The following vector line related corners (also called "cap") exist:

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=2000

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

Circles around input points with attribute transfer¶

v.buffer input=hospitals output=hospitals_circled type=point distance=1000 -t
# display buffer around hospital with category 36,
# this buffer is composed of several areas:
d.vect map=hospitals_circled type=area layer=1 cats=36
# extract this buffer, dissolving boundaries
v.extract in=hospitals_circled output=hospital_36_circled layer=1 cats=36 -d

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)

Buffer inside input areas¶

In this example, an internal buffer ("inward buffer" or "negative buffer") is generated using a negative distance value:

v.buffer input=lakes output=lakes_buffer type=area distance=-50

Internal buffer of 50m inside the "lakes" polygons (map subset, original areas shown in black)
Not all features are buffered, only the polygons that allow creation inside a topological cleaned polygon.