Data Model: Intersections

Use the intersection routines to calculate intersections between two feature classes. Intersections can be defined in the data model administrator and added to the industry model in the Industry Model task pane.

Examples: An intersection of the parcel feature class with the land use feature class determines the polygon sections of different land use for each parcel.

An intersection of the parcel feature class with the control point feature class determines all parcels where a control point is located.

Note: You can execute intersections between 3D feature classes, or between a 2D and a 3D feature class.

The following table shows the different types of intersections:

Intersection Type	Description
OO	Polygon with polygon Result: polygon feature class
OL	Polygon with line Result: line string feature class
LL	Line with line Result: point feature class
OP	Polygon with point Result: point feature class
LP	Line with point Result: point feature class

An intersection requires a primary and a secondary feature class. These feature classes can be identical. Therefore, for example, you can compare parcel areas before and after a modification.

Intersection feature class—The results of intersections are stored in the database in special target feature classes. Each intersection type has its own target feature class with certain default attributes. The intersection feature class is either created when the intersection is defined, or it is created explicitly by the user.

Intersections can be performed with a job, or without a job:

Intersection within a job—If the intersection is part of a job, the performance is dependent on the job change state of the feature class.

Intersection without jobs—In this case, you can start the process manually from the intersection context menu.

Note: The intersection feature class is not job-enabled due to dependencies between topics, if the primary and secondary feature classes are not in the same topic.

Getting Intersections Started

To work with intersections, you must have the following:

• Intersection definition (in the data model administrator).
• Intersection feature classes and intersections to be shown in the industry model explorer in the Industry Model task pane

You can start a predefined intersection manually. Use the predefined intersections for frequent intersections. To start an intersection in the data model administrator, right-click the intersection item and click Intersect.

Alternatively, in AutoCAD Map 3D toolset or Infrastructure Application Extension , use the industry model explorer in the Industry Model task pane. You can either intersect the whole area or select the areas of the primary feature class.

To start an intersection from the industry model explorer

1. In the industry model explorer, expand the Intersection node and select the intersection.
2. Right-click and click Intersect.
3. In the Select The Perimeter For The Intersection dialog box, select one of the following:

   Intersect Over Area (select features) and click Select.

   Intersect Over All (all features) and click OK.

Note: When selecting the perimeter in the drawing, use an appropriate Object Snap. For example, to select line features, use OSNAP = NEAREST.

Also, you can start an intersection and perform temporary and occasional intersections, by entering the parameters in dialog mode.

To start a temporary intersection

1. Start the data model administrator.
2. In the data model explorer, select the primary feature class. Right-click and click Intersect With.
3. Select the secondary feature class and double-click.

Under the topic Intersection, the target feature class is created with a name containing the names of the feature classes.

Note: If you want to repeat a temporary intersection with the same feature classes, you must drop the topic of the target feature classes beforehand.