NAME¶

v.buffer - Creates a buffer around vector features of given type.

KEYWORDS¶

vector, buffer, geometry

SYNOPSIS¶

v.buffer v.buffer help v.buffer [-sct] input=name [layer=integer] [ cats=range] [where=sql_query] [ type=string[,string,...]] output=name [distance= float] [minordistance=float] [angle= float] [bufcolumn=name] [scale=float] [ tolerance=float] [--overwrite] [-- verbose] [--quiet]

Flags:¶

-s

 

Make outside corners straight

-c

 

Don't make caps at the ends of polylines

-t

 

Transfer categories and attributes

--overwrite

 

Allow output files to overwrite existing files

--verbose

 

Verbose module output

--quiet

 

Quiet module output

Parameters:¶

input=name

 

Name of input vector map

layer=integer

 

Layer number

 

A single vector map can be connected to multiple database tables. This number determines which table to use.

 

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 = 10000

type=string[,string,...]

 

Feature type

 

Options: point,line,boundary,centroid,area

 

Default: point,line,area

output=name

 

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

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

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¶

Internal buffers for areas can be generated with negative distance values ("inward buffer" or "negative buffer"). Attributes are not transferred due to potential buffer overlap, which cannot be resolved automatically. Buffers for lines and areas are generated using the algorithms from the GEOS library.

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

Overlapping circles around input points with attribute transfer¶

# copy map to current mapset (for easier DB linking) g.copy vect=hospitals,myhospitals v.buffer input=myhospitals output=circles type=point distance=2000 # change original points to centroids: v.type in=myhospitals 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=myhospitals layer=1 key=cat driver=dbf \
database='$GISDBASE/$LOCATION_NAME/$MAPSET/dbf' v.db.select circles_db

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)

REFERENCE¶

SEE ALSO¶

r.buffer, v.parallel, v.extract, v.type, v.patch, v.db.connect

AUTHORS¶

Radim Blazek Rewritten by Rosen Matev (with support through the Google Summer of Code program 2008) Rewritten by Markus Metz (2011, 2012) Last changed: $Date: 2014-04-30 18:19:24 +0200 (Wed, 30 Apr 2014) $ Full index © 2003-2014 GRASS Development Team