Overlay Analysis¶

Use this dialog to perform overlay analysis on polygon data.

Where do I find the dialog?¶

In the toolbox in terrain model drawing, select Overlay Analysis...

Available Methods¶

There are three methods for overlay analysis:

Union
Intersection
Identity

Note

The methods only support the polygon data type. For union and intersection, you can have more than two layers, and the order does not matter. For identity, you can only have two layers, and the order is important.

Method	Number of Layers	Result (Output)
Union	Two or more layers	All properties from input and overlay layers
Intersection	Two or more layers	Only properties common to input and overlay layers
Identity	Two layers	Properties from the input layer (the first), split by the overlay layer (the second)

Examples of Overlay Methods¶

Union¶

Input layer 1

Input layer 1

Input layer 2

Input layer 2

Union result

Union: Combines all areas from both layers.

Intersection¶

Input layer 1

Input layer 1

Input layer 2

Input layer 2

Intersection result

Intersection: Shows only overlapping areas.

Identity¶

Input layer 1

Input layer 1

Input layer 2

Input layer 2

Identity result

Identity: Retains the input layer, but split by the overlay layer.