Buffer (Analysis)

Creates buffer polygons around input features to a specified distance.

Alternate tools are available for buffer operations. See the Pairwise Buffer and Graphic Buffer tool documentation for details.

Illustration

Usage

• As described in How Buffer works, an important feature of the Buffer tool is the Method parameter, which specifies how buffers will be constructed. The two basic methods for constructing buffers, Euclidean and geodesic, are described as follows:
  • Euclidean buffers measure distance in a two-dimensional Cartesian plane, where distances are calculated between two points on a flat surface. Euclidean buffers are appropriate when analyzing distances around features in a projected coordinate system in a relatively small area (such as one UTM zone).
  • Geodesic buffers account for the shape of the earth (an ellipsoid, or more properly, a geoid). Distances are calculated between two points on a curved surface (the geoid). Geodesic buffers are appropriate in the following circumstances:
    • The input features are dispersed (cover multiple UTM zones, large regions, or the entire globe).
    • The spatial reference (map projection) of the input features distorts distances to preserve other properties such as area.
    • The Planar option is the default. This option will automatically determine the method to use based on the coordinate system of the input.
      • If the input features have a projected coordinate system, Euclidean buffers will be created.
      • If the input features have a geographic coordinate system and you specify a Buffer Distance value in linear units (meters, feet, and so forth, as opposed to angular units such as degrees), geodesic buffers will be created.
      • This option produces the same result as the Buffer tool prior to ArcGIS 10.3.

      Note:

      You can change the coordinate system of a feature class using the Project tool, or you can set the Output Coordinate System environment before running the Buffer tool, and this coordinate system will be used when creating buffers.

      When using the Planar option, you can improve the accuracy of buffers created with projected inputs using a projection that minimizes distance distortion—such as an Equidistant Conic or an Azimuthal Equidistant projection—that is geographically appropriate for the input.

      Caution:

      If the negative buffer distance is large enough to collapse the polygon to nothing, a null geometry will be generated. A warning message will appear, and no null geometry features will be written to the output feature class.

      

    • You can use a field from the input to set the buffer distances. Both numeric and text fields are acceptable. In a text field, the buffer distance can be a number, such as 5, or a valid linear unit, such as 5 kilometers. If using a number without a linear unit, the buffer will be in the linear units of the input's spatial reference. If the input is in a geographic coordinate system, the buffer will be in meters. If the linear unit is not recognized, the buffer will be in the linear units of the input's spatial reference. To learn more about valid linear units, see Linear units.
    • Buffer operations do not support the transfer of z-values from the input to the output buffer features.
    • Buffer operations do not support the transfer of m-values from the input to the output buffer features.

      License:

      The Side Type parameter options Left , Right , and Exclude the input polygon from buffer and the End Type parameter option Flat are only available with an Desktop Advanced license.