Overlay Layers

Available in big data analytics.

The Overlay Layers tool combines two layers into a single layer using various methods including intersect, erase, union, identity, symmetrical difference, and update.

Workflow diagram

Examples

The following are example uses of the Overlay Layers tool:

• The department of environmental quality wants to monitor the impact of livestock grazing on the state's water quality. Biologists with the department need to determine where the land deemed to be grazing allotments intersects with certain watersheds. Overlay layers through an intersect operation can be used to browse intersecting areas.
• A development company wants to build a golf resort in one of three centrally located counties in its state. Before the company can begin planning, it needs to determine whether there is enough privately owned land in those counties available to purchase for the resort. Overlay layers through an erase operation can be used to remove the publicly owned lands from the selected counties.

Usage notes

Keep the following in mind when working with the Overlay Layers tool:

• Input and overlay layers can be point, line, or polygon features.
• Sliver features can be excluded based on the tolerance of the processing spatial reference.
• The key field specified for the Track ID, Start time, and End time options are dropped from the join schema provided to the tool.
• The following table outlines the available overlay operations per input and overlay geometry types:

  Input and overlay geometry types	Intersect	Erase	Union	Identity	Symmetric difference	Update
  Point and point
  Point and polyline
  Point and polygon
  Polyline and point
  Polyline and polyline
  Polyline and polygon
  Polygon and point
  Polygon and polyline
  Polygon and polygon

• The supported overlay methods and input geometries are described in the following table:

  Overlay method	Description
  Intersect	The features or portions of features in the overlay that overlap the input features are preserved. The input and feature geometry must be the same.
  Erase	The features or portions of features in the overlay features that overlap the input features are removed.
  Union	The result contains a geometric union of the input layer and overlay layer.
  Identity	The result contains features or portions of features of the input features and overlay features.
  Symmetric difference	The result contains features or portions of features of the input layer and the overlay layer that do not overlap.
  Update	The result contains the geometric intersection of features from the input layer and the overlay layer.

Parameters

The following are the parameters for the Overlay Layers tool:

Parameter	Description	Data type
Input layer	The input layer for the overlay operation.	Features
Overlay layer	The overlay layer for the overlay operation.	Features
Overlay operation	Specifies the type of overlay to be performed. Overlay operations include the following: Intersect—Computes a geometric intersection of the input layers. Features or portions of features that overlap in both the input layer and overlay layer are written to the output layer. Erase—Only those features or portions of features in the overlay layer that are not within the features in the input layer are written to the output layer. Union—Computes a geometric union of the input layer and overlay layer. All features and their attributes are written to the output layer. Identity—Computes a geometric intersection of the input features and identity features. Features or portions of features that overlap in both the input layer and overlay layer are written to the output layer. Symmetric difference—Features or portions of features in the input layer and overlay layer that do not overlap are written to the output layer. Update—Computes a geometric intersection of the input layer and overlay layer. All features and their attributes are written to the output layer.	String

Output layer

The output layer retains the same schema of the target layer and adds fields from the join layer with _overlay appended. Key fields specified, such as for the Track ID, Start Time, and End Time options, are dropped from the join schema provided to the Overlay Layers tool.