How To: Create a region or boundary map with no internal boundaries in ArcMap
This article describes how to create a region map without internal boundaries using the dissolve function of the GeoProcessing Wizard. The article uses the states theme found in the arcgis\arcexe82\Bin\TemplateData\USA directory as an example.
NOTE: This article does not address Region Polygons, see the ArcGIS Desktop Help for more information.
To create the region map, you must dissolve the features base on an attribute in the theme table. The dissolve will combine all of the features with the same value into one feature without internal boundaries. The states theme used in this example contains a Sub_region field you will use to dissolve the features.
Add states.shp from the arcgis\arcexe82\Bin\TemplateData\USA directory to the Data Frame.
Select GeoProcessing Wizard from the Tools menu to launch the GeoProcessing Wizard.
Select Dissolve features based on an attribute from the list of GeoProcessing options and click Next.
Select states.shp as the theme to dissolve.
Select Sub_region as the the attribute to dissolve.
Click the browse button next to the Output File to name and save the output theme.
Select any additional attributes you would like to summarize or aggregate and click Finish.
Symbolize the states theme with unique values based on the Sub_region field.
a. Right-click the states layer and select properties. b. Click the Symbology tab. c. Click Categories from the Show list on the left side of the dialog to select Unique values. d. Select Sub_region from the Value Field drop down list. e. Select the color scheme or the colors you want to use for each region. f. Click Add All Values and click OK to close the layer properties.
The final result should look similar to this:
Note: For more information on the dissolve function of the GeoProcessing Wizard and aggregating data, see "aggregating data" under the geoprocessing topic in the ArcGIS Desktop Help.