How Intersect (Analysis) works

The Intersect tool calculates the geometric intersection of any number of feature classes and feature layers. The features or portion of features that are common to (intersect) all inputs will be written to the Output Feature Class.

Intersect does the following:

To explicitly control the output spatial reference (coordinate system and domains), set the appropriate environments, the Output Z Aware, and Output M Aware.

The inputs can be any combination of geometry types (point, multipoint, line, polygon). The output geometry type can only be of the same geometry or a geometry of lower dimension as the input feature class with the lowest dimension geometry (point = 0 dimension, line = 1 dimension, poly = 2 dimension). Specifying different OUTPUT TYPE will produce different types of intersection of the input feature classes. These are not a different representation of the same intersections; they are intersections that can only be represented by that geometry type (point, line, or polygon).

Intersect can run with a single input. In this case, instead of discovering intersections between the features from the different feature classes or layers, it will discover the intersections between features within the single input. This can be useful to discover polygon overlap and line intersections (as points or lines).

Examples

Polygon feature class inputs

Polygons can intersect in three ways:

Polygon inputs and polygon output

The graphic below illustrates the result of intersecting two polygon feature classes with the Output Type parameter set to either POLY or the default (LOWEST). The output polygon features are where a polygon from one of the input feature classe or layer intersects a polygon from the other input feature class or layer.

Intersect polygons

Polygon inputs and line output.

The graphic below illustrates the result of intersecting two polygon feature classes with the Output Type parameter set to LINE. The output line features are where a polygon from one of the input feature classes share a common boundary (intersect at a line) with a polygon from the other input feature class.


Intersect polygon with line

Polygon inputs and point output

The graphic below illustrates the result of intersecting two polygon feature classes with the Output Type parameter set to POINT. The output point features are where a polygon from one of the input feature classes has a vertex intersecting the boundary (intersect at a point) of a polygon from the other input feature class.


Intersect polygon with point

Line feature class inputs

When all the inputs are line feature classes, the intersect tool can be used to determine where the features from the input feature classes overlap and intersect at points and lines.

Line inputs and line output. The graphic below illustrates the result of intersecting two line feature classes with the Output Type parameter set to either LOWEST or LINE. The output line features are where a line from one of the input feature classes overlaps a feature from the other input feature class.


Intersect lines illustration

Line inputs and point output

The graphic below illustrates the result of intersecting two line feature classes with the Output Type parameter set to POINT. The output point features are where a line from one of the input feature classes crosses a feature from the other input feature class.


Intersect line and point

Point feature class inputs

When all the inputs are point feature classes, the intersect tool can be used to determine which points are common to all input feature classes.

Intersect with point inputs

Mixed geometry feature class inputs

Intersect can be used with feature classes of different geometries. The default (and highest allowable) Output Type is the same as the feature class with the lowest dimension geometry.

Polygon and line input for line output

The graphic below illustrates the result of intersecting a line and polygon feature classes with the Output Type parameter set to LINE. The output line features are where a line from one of the input feature classes overlaps a polygon from the other input feature class.

Intersect poly on lines for line

Polygon and line input for point output

The graphic below illustrates the result of intersecting a line and polygon feature classes with the Output Type parameter set to POINT. The output point features are where lines touch at a point on the polygon boundary.


Intersect poly on lines for point

Polygon, line, and point input for point output

The graphic below illustrates the result of intersecting point, line, and polygon feature classes. The output can only be a point feature class. Each point in the output will intersect at least one feature in each of the input feature classes.

Intersect poly on line for point