Combining features

Another way to create new features is by combining existing features into a new feature stored in the same feature class or in a different feature class.

Merge

The Merge function combines selected line or polygon features into a single new feature. The lines or polygons being merged must exist in the same feature class. The original features are removed and replaced with the new feature. You can choose which feature's attributes are retained.

Two parcels are merged to create one new feature in the same feature class.

Union

You can also combine features using the Union function. Union combines features stored in the same feature class or in different feature classes. Although the features may be from different feature classes, their geometry type must be the same, either line or polygon. The output of a Union is a new feature in the target layer—the original features are preserved. The new feature has no user-defined attributes. If you want the feature created from a union to be added to a new (empty) feature class, you will first need to create the new feature class.

In this example, two parcels from different feature classes are combined using Union. The new parcel is stored in a third feature class.

Intersect

As with Union, the result of combining features with the Intersect function is a new feature in the target layer. Intersect creates a new feature from the area where features overlap. You can find the intersection between features stored in different feature classes, but they must be of the same geometry type, either line or polygon. The original features are maintained, and the new feature is created with no user-defined attributes. If you want the new feature created from an intersect to be added to a new (empty) feature class, you will first need to create the new feature class.

Two polygons from different feature classes are intersected. The resulting new polygon represents the area common to both features and is stored in a different feature class.