In ArcGIS, how do I create an island polygon?
Sometimes you need to create a polygon with a hole in it, or even a polygon with both a hole and an interior polygon. To create these kinds of polygons, you need to create a multipart feature. When you create a polygon with an island inside it, the outer and inner areas are all one feature. This means that clicking either polygon will select both of them, and the attributes of the feature are stored in just one row in a table. Donut polygons are commonly used with administrative boundaries. For example, a city may have unincorporated areas within its limits.
For more about editing polygons, see Creating adjoining polygons from ArcGIS Resources. For more about editing polygons with holes, see Creating new donut holes and island polygons, also from ArcGIS Resources.
The information in this document was adapted from the ArcGIS Help 10.1 article Creating new donut holes and island polygons.
Last modified on March 06, 2013.