Display the sum of attribute values in an ArcGIS Pro layout legend

Summary

When creating a map layout with a legend, displaying the sum of attributes help users to visualize the scope of attributes displayed on the map. This visualization is useful for planning or analysis purposes. Examples of summary of attributes include the total count of housing in a residential area, or the total length of streets in an area.

The image below shows a map with a feature class called Pathways.

In the Pathways attribute table, the pathways are classified by street names, and the length of each feature is specified. In this article, the total length of each street is determined.

Procedure

1. Launch the ArcGIS Pro project.
2. Summarize the preferred field.
   1. In the Contents pane, right-click the feature class, and click Attribute Table. In this case, Pathways is selected.
   2. In the attribute table, right-click the field header, and click Summarize. In this example, the StreetName field is selected.
   3. In the Summary Statistics dialog box, for Input Table, click the drop-down menu and select the desired feature class. In this example, Pathways is selected.
   4. Edit the Output Table name as required, and click Browse to specify a location for the output stand-alone table.
   5. For Statistics Fields, click the Field drop-down menu and select the attribute field to summarize. In this example, Shape_Length is selected.
   6. Click the Statistic Type drop-down menu, and click Sum.
   7. For Case Field, select the field used to calculate statistics separately for each unique attribute value. The field selected is used as the join field.
   8. Click OK.

A stand-alone table is created and added to the Contents pane.

3. Add a join between the preferred feature class and the newly created stand-alone table from Step 2. In this example, Pathways and Pathways_SummarizeAttributes are selected.
   1. In the Contents pane, right-click the feature class, and click Joins and Relates > Add Join.
   2. In the Add Join dialog box, for Input Join Field, click the drop-down menu and select the case field used for the summary statistics table. In this example, Streetname is selected.
   3. For Join Table, click the drop-down menu, and select the stand-alone table created in Step 2.
   4. For Join Table Field, click the drop-down menu, and select the matching field selected in Step 3b.
   5. Click Validate Join.
   6. In the Validate Join pop-up window, click Close.
   7. In the Add Join dialog box, click OK.

4. Symbolize the joint feature class. In this example, Pathways is symbolized.
   1. In the Contents pane, right-click the feature class to be symbolized, and click Symbology. In this example, Pathways is selected.
   2. In the Symbology pane, click the Primary Symbology tab.
   3. Click the Primary Symbology drop-down menu, and select Unique Values.
   4. For Field 1, click the drop-down menu and select the field used to summarize in Step 2.
   5. Click Add field, and for Field 2, click the drop-down menu, and select the summarized attribute. In this example, it is SUM_Shape_Length.

5. Add a layout. In the layout view, add a legend that represents the summarized features created in Step 4.

The image below displays the sum of attribute values in an ArcGIS Pro layout legend. The pathways are separated and symbolized by StreetName, and the legend also displays the total length of each street.