Click the Features | New Features | Split command or right-click on a selected polygon and click Split Islands/Lakes to break a single complex polygon into multiple polygons. A new polygon is created for each of the polygons contained in the complex polygon.
The new polygons use the line and fill properties from the original complex polygon. The object name is also retained from the original complex polygon.
Complex polygons can contain polygons that are touching, intersecting, completely separate, or contained completely within other polygons. Each individual polygon in the group is called an island. An example of islands that can form a complex area is the Hawaiian islands. When a polygon is completely contained inside another polygon, a lake is formed. Lakes are the holes in a complex polygon. When the islands and lakes are split, each island and lake becomes a new polygon.
Note about Base Maps
If objects should be edited in a base map, click on the object in the Base layer to select it. Click the Features | Group | Start Editing command to enter editing mode. Select the polygon to be split. Then, click the Features | Islands/Lakes | Split command. The new polygons are created from the single complex polygon. Click the Features | Group | Stop Editing to end object editing mode in the base map.
Splitting a Complex Polygon into Multiple Polygons
Click on a complex polygon in the Contents window. The polygon can be imported with the Home | Insert | Graphic command or can be created by combining multiple polygons into a single complex polygon using the Combine command.
Click on the complex polygon in the Contents window or in the plot window.
Click the Features | New Features | Split command or the button. Multiple polygons are created from the single complex polygon. Both polygons maintain the properties of the original polygon.
The polygon is split into multiple polygons. Each polygon can be individually selected and edited.