The Find Hot Spots tool identifies statistically significant spatial clustering of high values (hot spots) and low values (cold spots) or data counts using the Getis-Ord Gi* statistic.
Examples
Example uses of this tool include the following:
- The local police department wants to identify where there are clusters of violent crimes and high unemployment rates in the city. The department uses the Find Hot Spots tool to identify statistically significant violent crime and unemployment hot spots.
- A conservation officer wants to identify where there are clusters of diseased trees in the forest. The officer will use the results to direct treatment and conservation efforts. The Find Hot Spots tool will be used to identify the regions with statistically significant diseased (hot spots) and healthy (cold spots) trees.
Usage notes
The Find Hot Spots tool includes configurations for input features, hot spot settings, and the result layer.
Input features
The Input features group includes the Input layer parameter, which is the layer that contains the point or polygon features on which hot spot analysis will be performed.
For feature inputs, a count of features is displayed below the layer name. The count includes all features in the layer, except features that have been removed using a filter. Environment settings, such as Processing extent, are not reflected in the feature count.
Note:
Web Mercator is not an appropriate projection for spatial analysis. If the spatial reference system of the input layer is WGS 1984 Web Mercator (Auxiliary Sphere), the data will be converted to a geographic coordinate system to use chordal distances in the analysis.
Hot spot settings
The Hot spot settings group includes the following parameters:
- Variable type determines whether analysis is performed on the feature counts or values. The options are as follows:
- Field—Analysis will be applied to the values of the field specified by Analysis field.
- Point counts—Point features will be aggregated into polygons or cells and counted. Analysis will be applied to the aggregated point counts. This option is available when the input layer is point features.
Note:
Variable type is not available in ModelBuilder.
- Analysis field is the field that will be analyzed for clusters of high values (hot spots) and low values (cold spots). This parameter is available when Field is specified for Variable type.
- Divide by specifies how the values are divided in the analysis field or the aggregated point counts. The options are as follows:
- Field—The field in the input layer or aggregation polygon layer (if applicable) that will be used to divide the analysis field values or point count.
- Enrichment data—The features or aggregation shape will be enriched with Esri population data; then the analysis field values or the aggregated point counts will be divided by the population if the Esri Population is specified. The source of the Esri population data is Esri Demographics Global Coverage. This option uses ArcGIS GeoEnrichment Service and consumes additional credits.
Note:
Enrichment data is not available in ModelBuilder.
Aggregation shape type specifies the shape of the cells within which the point features will be aggregated. This parameter is available when Point counts is specified for Variable type
The options are as follows:- Fishnet cells—Point features will be aggregated within fishnet cells.
- Hexagon cells—Point features will be aggregated within hexagon cells.
- Polygon layer—Point features will be aggregated within the polygon features specified by Aggregation polygon layer.
- Aggregation polygon layer is the layer that contains the polygon features within which the points will be aggregated. This parameter is available when Polygon layer is specified for Aggregation shape type.
- Define where points are possible is the layer that will define the extent of the analysis. You can choose a layer using the Layer button or use the Draw input features button to create a sketch layer to use as the input. Points that fall outside of the bounds of the layer will not be included in the analysis. This parameter is available when either Fishnet cells or Hexagon cells is specified for Aggregation shape type.
Note:
Draw input features is not available in ModelBuilder.
- Cell size is a numeric value that defines the length of a side of each cell.
- Cell size unit is the units that will be used for the cell size. Supported units are feet, miles, meters, and kilometers.
- Distance band is a numeric value that defines the distance from a target feature that will be included in a target feature's neighborhood. All of the features that fall within the distance band will be included in the target feature's neighborhood. The entire neighborhood will be analyzed to determine whether the target feature is a statistically significant hot or cold spot.
- Distance band unit is the units of the distance band. Supported units are feet, miles, meters, and kilometers.
Result layer
The Result layer group includes the following parameters:
- Output name specifies the name of the layer that is created and displayed. The name must be unique. If a layer with the same name already exists in your organization, the tool will fail and you will be prompted to use a different name.
- Save in folder specifies the name of a folder in My content where the result will be saved.
Limitations
The following limitations apply to the tool:
- If Variable type is specified as Point counts, the following limitations apply:
- The input layer must contain at least 60 point features.
- At a minimum, 30 aggregation cells or polygons must contain at least one point feature.
- The point counts within the aggregation cells or polygons cannot be identical. There must be variation in the point counts between aggregation cells or polygons.
- If Variable type is specified as Analysis field, the following limitations apply:
- At a minimum, 30 features must contain non-null values in the specified analysis field.
- The values in the specified analysis field cannot be identical. There must be variation in the values.
- At a minimum, 30 points must fall within the bounding area specified by Define where points are possible.
- The cell size value cannot exceed the distance band.
- The availability of Esri population data will depend on the location of the input features.
- Esri population data is not available for the Divide by parameter when your organization has a custom GeoEnrichment Service configured.
- The Draw input features button is not available in Scene Viewer.
Environments
Analysis environment settings are additional parameters that affect a tool's results. You can access the tool's analysis environment settings from the Environment settings parameter group.
This tool honors the following analysis environments:
- Output coordinate system
- Processing extent
Note:
The default processing extent is Full extent. This default is different from Map Viewer Classic in which Use current map extent is enabled by default.
Credits
This tool consumes credits.
Use Estimate credits to calculate the number of credits that will be required to run the tool. For more information, see Understand credits for spatial analysis.
Outputs
The tool outputs a layer where the features are the input features or the aggregation cells or polygons containing at least one point. The layer contains the results of the hot spot analysis. It includes fields for the p-value, z-score, confidence level bin, statistical significance, and the number of neighbors used in the analysis.
To view additional details about the analysis, open the History pane and find and click the successful tool run. The analysis details will open on the Results tab. The Results tab includes additional details about the analysis. You can also view the additional details on the layer's item page. Click the options button next to the output layer and click View details.
Note:
In ModelBuilder you can only view the additional details about the analysis on the output layer's item page.
Licensing requirements
This tool requires the following user type and configurations:
- Creator, Professional, or Professional Plus user type
- Publisher, Facilitator, or Administrator role, or an equivalent custom role
The GeoEnrichment privilege is required to use Esri population data.
Resources
Use the following resources to learn more:
- Find Hot Spots in ArcGIS Pro
- Hot Spot Analysis (Getis-Ord Gi*) in ArcGIS Pro
- Find Hot Spots in ArcGIS REST API
- find_hot_spots in ArcGIS API for Python