Display the symbologies of multiple layers in ArcMap after merging them

Summary

In ArcMap, merging layers using the Merge tool creates a layer represented by a default unified symbol. Since only one symbol is used to represent the merged layers, differentiating the layers can be difficult. This article describes how to display the symbols of the input layers after merging them.

In this example, the Water Meter and Water Hydrant layers of a water company are merged into a single layer labelled WaterMeters_Merge1. However, the output layer does not retain the symbols of the input layers, as shown in the image below.

Procedure

Complete the steps below in the sequence it is presented.

Add a common field to the input layers

1. In the Content window, right-click the input layer and click Open Attribute Table.
2. Click the Table Options drop-down list and select Add Field....
3. Configure the parameters in the Add Field window as follows:
   1. For Name, assign a name to the new field. In this example, it is UtilityTyp.
   2. For Type, select Text from the drop-down menu.
   3. Click OK.

4. Right-click the new field header on the attribute table and click Field Calculator.
5. In the Expression window, use the following code to fill in the field with the input layer name:

"<Layer Name>"

For this example, the code used is:

"Water Hydrant"

6. Click OK.
7. Repeat steps 1 through 6 for all subsequent input merge layers.

Merge the layers using the Merge tool

1. In the Catalog window, navigate to System Toolboxes > Data Management Tools > General and click Merge.
2. Configure the parameters in the Merge window as follows:
   1. For Input Datasets, select all the layers to be merged from the drop-down menu. In this example, it is Water Meters and Water Hydrants.
   2. For Output Datasets, specify a name and file location for the output merged layer.
   3. Click OK.

​​​​Assign the input layer symbols

The common fields of both the input layers' attribute tables, added at the beginning, are merged in the newly merged layer. This field is used to assign the symbols of the input layers.

1. In the Content window, right-click the merged layer and click Properties.
2. In the Layer Properties window, navigate to the Symbology tab.
3. In the Show section, click Categories and select Unique values.
4. For Value Field, select the newly added field from the drop-down menu. In this example, it is UtilityTyp.
5. Click Add All Values to add all the field values to the list.
6. Assign the appropriate symbols to all the values. Refer to ArcMap: Symbolizing data based on unique attribute values for more information.
7. Click OK.

The merged layer displays the input layer symbols, as shown in the image below.