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.
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 will use the results to select high schools that will benefit most from its summer job program. 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.
The Find Hot Spots tool includes configurations for input features, hot spot settings, and the result layer.
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.
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 in order 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.
- 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 determines how to divide the values in the analysis field or the aggregated point counts. The options are as follows:
- Field—The field in the input layer that will be used to divide the analysis field values.
- Enrichment data—Enriches the features or aggregation shape with Esri population data then divides the analysis field values or the aggregated point counts by the population, if Esri Population is specified. The source of the Esri population data is Esri Demographics Global Coverage. This option uses GeoEnrichment services and will consume additional credits.
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 typeThe 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 specifies 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. 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.
- 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.
The Result layer group includes the following parameters:
- Output name determines the name of the layer that is created and added to the map. 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.
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.
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:
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.
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.
You can view additional details about the analysis on the output layer's item page. To access the layer's item page, click Analysis on the Settings toolbar. Click History, and find and click the successful tool run. The analysis details will open on the Results tab. Click the options button next to the output layer, and click Open item details.
This tool requires the following licensing and configurations:
- Creator or GIS Professional user type
- Publisher, Facilitator, or Administrator role, or an equivalent custom role
The GeoEnrichment privilege is required to use Esri population data.
Use the following resources to learn more: