The Summarize Center and Dispersion
tool finds central features and directional distributions.
Workflow diagram
Examples
- A local government is planning to open a new library for an underserved community. Centroids from block groups with the appropriate zoning and available lots have been collected. The Central feature option of Summarize Center and Dispersion, with a weight on population, can be used to choose the central block group that will serve the community best.
- A GIS analyst is analyzing the locations of 911 calls and the locations of emergency response stations (police, fire, and ambulance). The Mean center option of Summarize Center and Dispersion can be used to compare the mean center of the emergency calls and the mean center of the response stations.
- A crime analyst wants to determine if the mean center for burglaries shifts when evaluating daytime versus nighttime incidents. The Median center option of Summarize Center and Dispersion with a group by time of day can be used to determine where crimes are happening during the day and at night.
- A GIS analyst for a non-governmental organization is analyzing the spread of an infectious disease. The Ellipse option of Summarize Center and Dispersion can be used to model the outbreak.
Usage notes
The input for Summarize Center and Dispersion is a point, line, or area layer.
Select a summary method from the Summary types parameter.
| Summary type | Description |
|---|---|
Central feature | Identifies the most centrally located feature in a dataset. |
Mean center | Identifies the geographic center (or the center of concentration) for a set of features. |
Median center | Identifies the location that minimizes overall Euclidean distance to the features in a dataset. |
Ellipse | Creates standard deviational ellipses to summarize the spatial characteristics of geographic features: central tendency, dispersion, and directional trends. The ellipses can be sized as 1, 2, or 3 standard deviations. |
The Weight by field is used to weight locations according to their relative importance. For example, stores in a retail chain could be weighted by total sales.
The Group by field is used to group features for separate computations of central features or dispersion. For example, wildlife observations taken throughout the year could be grouped by season or month.
Similar tools
Use Summarize Center and Dispersion to find central features and directional distributions in your data. Other tools that may be useful are the following:
Map Viewer analysis tools
If you want to find the representative center of multipoint, line, or area features, use the Find Centroids tool.
ArcGIS Desktop analysis tools
Summarize Center and Dispersion performs the function of the Central Feature, Mean Center, Median Center, and Directional Distribution (Standard Deviation Ellipses) tools.