The concept of areas of influence can be compared to the ripple effect caused by a drop of water, generating waves that propagate from the point of origin. In spatial analysis, these influence zones are polygon features created around a point, line, or polygon entity, extending a specified distance. This technique is crucial for understanding the spatial extent affected by different activities, such as building a factory, constructing a road through a protected area, measuring the dispersion of pollutants like fertilizers, or determining the range of communication and radar antennas.
ArcGIS Pro offers tools specifically designed to generate these areas of influence: Buffer and Pairwise Buffer. These tools are located at:
- Geoprocessing > Toolboxes > Analysis Tools > Proximity > Buffer
- Geoprocessing > Toolboxes > Analysis Tools > Pairwise Overlay > Pairwise Buffer
The Buffer tool requires specific configuration parameters to properly generate influence zones. The essential options are:
- Input Features: Select the layer that contains the features to be buffered. This layer can include points, lines, or polygons (e.g., buffer_points, buffer_line, or buffer_polygon).
- Output Feature Class: Choose the location in a directory or geodatabase where the resulting buffered features will be saved.
- Distance [value or field]: This setting offers two methods of defining buffer distance. The Linear Unit option allows for the input of a fixed value and its unit (for example, 30 meters). The Field option enables the creation of buffers with varying distances based on values from a specified field in the attribute table.
- Method: This defines how the buffer is calculated. The Planar method uses Euclidean distance as measured on a flat surface, suitable for projected coordinate systems. The Geodesic method calculates distances based on the Earth’s curvature, providing more accurate results over large areas or when working with geographic coordinate systems.
Once configured, the tool generates a new layer representing the buffer zones around the selected features, based on the specified parameters.
Configuration of the “Buffer” tool.
An example output shows buffers created for three points, one line, and two polygons. A uniform distance of 20 meters was used, and the planar method was selected to generate these zones.
Zones of influence created using the “Buffer” tool.
