Find the point nearest to the center of the densest area in a heat map in ArcGIS Pro

Summary

ArcGIS Pro provides the ability to symbolize clusters of points as a heat map that displays the relative density of points in a dynamic raster visualization. Each cell in the raster visualization has a value that represents relative density based on the feature count or Weight field. The density is weighted by an attribute. For example, the heat map symbology of point features representing the distribution of stores is weighted by the monthly profit of each store so that stores with higher profits have a greater contribution to the calculation of density.

In some instances, it is necessary to find which points in the clusters are located nearest to the densest area of a heat map for further analysis. This is possible by finding the center point of the densest area in a heat map using ArcGIS tools, and finding the point that is nearest to the center point.

Procedure

To find the point located nearest to the center of the densest area in a heat map, use the following workflow:

1. In an ArcGIS Pro project, add the point feature class containing the points to create the dynamic heat map.
2. Create a heat map symbology for the added point layer. Refer to Draw a layer with heat map symbology for steps to do this.
3. Convert the heat map to a static map. Refer to Static heat map for steps to do this.
4. Calculate statistics for the static heat map using the Calculate Statistics tool.
   1. Click Browse to browse the static heat map for Input Raster Dataset, and click OK.
   2. Set other parameters as desired and click Run.
5. Make a copy of the static heat map with the calculated statistics using the Copy Raster tool.
   1. Select the heat map that has the statistics calculated for Input Raster Dataset.
   2. Select a Pixel Type.
   3. Set other parameters as desired and click Run. A new copy of the heat map raster is added to the project.
6. Convert the copy of the heat map to a polygon feature class using the Raster to Polygon tool.
   1. Select the raster recently added to the project for Input raster.
   2. Set the name of the Output polygon features and click Run. A new polygon layer is added to the Contents pane.
7. Extract the polygons with the highest gridcode value. These polygons represent the densest area in the heat map.
   1. Right-click the polygon layer in the Contents pane, and select Attribute Table.
   2. Right-click the gridcode field (or gridco) in the attribute table, and select Sort Descending to set the attributes list with the highest value polygons at the top.

In this example, only one polygon has the highest value. If more than one polygon has the same highest value, merge the polygons into one using the Merge tool in the Edit tab.

3. Right-click the layer in the Content pane, and select Properties.
4. Select Definition Query in the Layer Properties window.
5. Click New definition query, and set a query to display only the feature with the highest value. Click Apply to apply the query and click OK.
6. Right-click the polygon layer in the content pane, and select Data > Export Features.
7. In the Feature Class to Feature Class pane, fill in the required fields, and select Run.

A new polygon layer is added to the Contents pane. This layer contains only one polygon with the highest gridcode value.

8. Use the Feature To Point tool to find the geometric center of the polygon and output a point layer.
   1. Select the output layer from Step 7 for Input Features.
   2. Set a name for the Output Feature Class and click Run. A new point layer representing the center of the densest area is added to the map.
9. Re-symbolize the original point layer as Single Symbol.

10. Find the point from the original point layer that is nearest to the center of the densest area using the Near tool.
    1. Select the point layer extracted in Step 8 for Input Features.
    2. Select the original point layer for Near Features.
    3. Set other parameters as desired, and click Run.
    4. Once the tool is run, open the attribute table for the point layer used as the input. A new column with the name NEAR_FID is added containing the Object ID of the closest near feature.

11. Identify the point that matches the Object ID from the Near tool output in the original point layer. This point is the nearest to the center of the densest area in the heat map.