Buffer (Coverage)


Creates buffer polygons around specified input coverage features.

Learn more about how Buffer works


Buffer illustration



Buffer_arc (in_cover, out_cover, {feature_type}, {buffer_item}, {buffer_table}, {buffer_distance}, {fuzzy_tolerance}, {buffer_shape}, {buffer_side})
ParameterExplanationData Type

The coverage containing features to be buffered.


The polygon buffer coverage to be created.


The feature class to be buffered:

  • LINEArcs will be buffered. This is the default option.
  • POLYPolygons will be buffered.
  • POINTPoints will be buffered.
  • NODENodes will be buffered.

An item in the feature attribute table of input coverage whose value is used as the feature's buffer distance. If a buffer table is used, the buffer item functions as a lookup item in the buffer table.


An INFO lookup table that lists a buffer distance for each buffer item. A buffer table can be specified only if the buffer item is specified. The buffer table contains at least two items:

  • Buffer Item—Defined the same as buffer item in the input coverage feature attribute table. The buffer table must be sorted on this item in ascending order.
  • DIST—The buffer distance for each buffer item value. DIST must be defined as a numeric item (that is, N, I, F, or B). A lookup table will categorize item values.
ArcInfo Table

The distance used to create buffer zones around input coverage features when buffer item and buffer table are not specified. The default buffer distance is 0.125 coverage units. This default buffer distance will be applied whenever a value for this parameter is not specified.

The smallest buffer distance that can be computed is 0.00000005 coverage units. Specifying a buffer distance below this threshold will result in an empty output coverage. For polygon features, if a negative buffer distance is used, buffers will be generated on the insides of polygons.


The minimum distance between coordinates in the out_cover. By default, the minimum fuzzy tolerance value from the in_cover is used.


For lines, the shape of the buffer at the line endpoints.

  • ROUNDWill make an end in the shape of a halfcircle.
  • FLATWill construct rectangular line endings with the middle of the short side of the rectangle coincident with the endpoint of the line.

For lines, the topological side on which the buffer may be generated.

  • FULLOn all sides. This is the default.
  • LEFT"Half buffer" on the topological left side of a line.
  • RIGHT"Half buffer" on the topological right side of a line.

Code Sample

Buffer example (stand-alone script)

The following stand-alone script demonstrates how to create a buffer around a road coverage.

# Name: Buffer_Example.py
# Description: Creates a buffer around a road coverage.
# Requirements: ArcInfo Workstation
# Author: ESRI

# Import system modules
import arcpy
from arcpy import env

# Set environment settings
env.workspace = "C:/data"

# Set local variables
inCover = "road"
outCover = "C:/output/roadbuf"
featureType = "LINE"
bufferDistance = 200
bufferShape = "ROUND"
bufferSide = "FULL"

# Execute Buffer
arcpy.Buffer_arc(inCover, outCover, featureType, "", "", bufferDistance, "",
                 bufferShape, bufferSide)


Related Topics

Licensing Information

ArcView: No
ArcEditor: No
ArcInfo: Requires ArcInfo Workstation installed

Published 6/8/2010