By Aileen BuckleyEsri Cartographer
Feathering is a technique that makes the area you want to highlight on your map stand out. This helps your map readers focus on the area that's important on the map. With feathering, you can fade a dark edge of any color into the background. In the first map below, only the data gives you a clue about the area of interest. In the second map, the feathered edge makes the area of interest stand out.
Without feathering, only the data gives you an idea of the area of interest on the map.
Feathering makes the primary area of interest—Oregon—stand out.
Feathering involves the use of multiple buffer rings symbolized using transparency. This technique works really well when you overlay your data on an ArcGIS Online basemap and want to show the area of interest in addition to the data. Using transparency allows you to see through the feathered edge to the background, whereas symbolizing the buffers without transparency obscures background features. In the close-ups below, features below the feathered edge, such as the rivers and labels, remain partially visible.
Feathering allows the background to remain visible.
To create the feathering effect in ArcMap, you will use the Multiple Ring Buffer tool, which is available at all ArcGIS license levels—Basic, Standard, and Advanced. You will also use a polygon feature class that represents the extent of your area of interest. You will follow three steps to create this effect: create the buffers, add a transparency attribute, and symbolize the buffers.
The result: A set of transparency values that will be used to symbolize the feathered edge in the final step.
The transparency values in the attribute table range from about zero for the nearest buffer ring to 100 for the farthest buffer ring.
To learn more about feathering and other cartographic design techniques, read Make Maps People Want to Look At.