Click the Features | Islands/Lakes | Combine command or right-click on multiple selected polygons and click Edit Boundaries | Combine Islands/Lakes to combine multiple polygons into a single complex polygon. A new complex polygon containing all of the selected polygons is created.
The new polygon uses the line and fill properties from the lowest selected polygon in the Contents window. The object name is also retained from the lowest selected polygon in the Contents window.
Complex polygons can be created from polygons that are touching, polygons that are completely separate, or polygons that are 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.
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 all of the polygons to be combined. Then, click the Features | Islands/Lakes | Combine command. The polygons are combined into a single complex polygon. Click the Features | Group | Stop Editing command to end object editing mode in the base map.
Click the Polygon command.
On the plot window, click several points. Double-click the last point to close the polygon.
Repeat step 2 a few more times so that several polygons are created.
Press ESC on the keyboard to end drawing mode.
In the Contents window, click on the first polygon that you want to combine.
Hold down the CTRL key on the keyboard.
In the Contents
window, click on the each additional polygon that you want to combine.
In this example, the top and bottom polygons are selected in the Contents window and in the plot window.
Click the Features | Islands/Lakes | Combine command. A single polygon is created from the selected polygons. Both polygons have the properties of the bottom-most polygon in the Contents window.
The two polygons become a single complex polygon.
Polyline to Polygon
Polygon to Polyline