Buffer (Analysis)

Usage tips

• Features will not be buffered if their buffer distance is zero. If you don't want to have a feature buffered in the Output Feature Class, assign it a buffer distance value of zero in the distance field.

• Negative distances can be used when buffering polygon features, to create buffers on the inside of the polygon features. Using a negative value will shrink the output polygon feature by the distance specified.

• The LEFT and RIGHT options generate buffers at the topological left or right of a line. Caution must be exercised in interpreting the left or right side of a polyline. With connecting polylines, the left side of one polyline may be on the right side of another connecting polyline.

• Using the Dissolve Type parameter ALL option will dissolve all buffer polygons into a single multipart polygon feature. Buffers of related features can be dissolved together using the Dissolve Type parameter LIST option and a set of fields for Dissolve Fields. Buffer features with the same values in their Dissolve Fields will be dissolved together.

• Using ALL or LIST for the Dissolve parameter may result in multipart features being created.

• The Side Type and End Type parameters apply only to line features.

• Side Type's LEFT and RIGHT options and End Type's FLAT option are only available with an ArcInfo licence.

• Buffer will expand the XYDomain of the Output Feature Class to accommodate potential buffer features beyond the Input Feature's XYDomain.

• Using the Dissolve Type parameter's NONE option will add a 'BUFF_DIST' field to the Output Feature Class that will show the buffer distance used for each feature.

• The buffered edges of a LEFT or RIGHT side buffer are different from those created by a FULL buffer due to differences in the algorithms used to create the buffers. When using the LEFT or RIGHT option, a vertex is placed at every degree along the point of rotation, the value is smaller using the FULL option, which creates a smoother line. The difference between the two is within the precision of the Input Features.

• Buffer can create very large multipart polygon features when using the Dissolve option. This is especially true when using a small number of Dissolve Field(s) or when dissolving all polygons into a single polygon. Very large polygon features may cause display problems and/or have poor performance when drawn on a map or when edited. To avoid these potential problems, use Multipart To Singlepart on Buffer's output to split larger multipart features into many smaller features.

• When using the results of Buffer as input to an overlay operation such as Union or Intersect, it is recommended that Buffer output be dissolved in order to reduce the number of features and overlap. This can be done when only a subset of the Input Feature's attributes are necessary for the analysis being performed. This will reduce the number of spatial relationships between the input features being processed, thereby reducing the amount of memory the tool requires and the amount of time required for processing.

• The Dissolve Fields parameter Add Field button is used only in ModelBuilder. In ModelBuilder, where the preceding tool has not been run, or it's derived data does not exist, the Dissolve Fields parameter may not be populated with field names. The Add Field button allows you to add expected fields so you can complete the Buffer dialog and continue to build your model.

• The following environments affect this tool: configKeyword, extent, MDomain, outputCoordinateSystem, outputMFlag, outputZFlag, outputZValue, scratchWorkspace, spatialGrid1, spatialGrid2, spatialGrid3, workspace, XYDomain, and ZDomain.

Command line syntax
An overview of the Command Line window
Buffer_analysis <in_features> <out_feature_class> <buffer_distance_or_field> {FULL | LEFT | RIGHT} {ROUND | FLAT} {NONE | ALL | LIST} {dissolve_field;dissolve_field...}

Command line example

Buffer_analysis c:\basedata\road.shp c:\basedata\buffered_roads.shp '200 Feet' FULL FLAT

Scripting syntax
About getting started with writing geoprocessing scripts
Buffer_analysis (in_features, out_feature_class, buffer_distance_or_field, line_side, line_end_type, dissolve_option, dissolve_field)

Script example

import arcgisscripting
gp = arcgisscripting.create()
gp.workspace = "c:/basedata"
gp.toolbox = "analysis"

# Buffer roads.shp based on each road feature's value in the Distance field,
#  and dissolve buffers into groups according to values from Road_Type field.
gp.buffer("roads.shp", "buffered_roads.shp", "Distance", "FULL", "ROUND", "LIST", "Road_Type")