Scenarios for generating and updating intersections

Disponible avec la licence Location Referencing.

The Generate Intersections tool generates new intersections and updates existing intersections. Scenarios to generate and update intersections are detailed in the following sections.

Intersections and conflict prevention

When conflict prevention is enabled, the following conditions affecting intersecting routes apply.

• If conflict prevention is not enabled, and the routes aren't locked during intersection calculation, you are responsible for reconciling any intersection conflicts with the parent version. This is done by accepting (reconciling) route changes in the edit version from the parent and recalculating intersections.
• If conflict prevention is enabled, all routes that intersect with routes for which intersections are being calculated are also locked.

In the following example, Route D is selected (highlighted in yellow) before running Generate Intersections. Since Routes AA, BB, CC, and DD intersect with Route D, locks need to be acquired for all those routes.

No locks are present before running the tool.

Before generating intersections, routes D, AA, BB, CC, and DD are locked (highlighted in green).

Locks are acquired on intersecting routes.

The tool fails in cases where locks are not available for intersecting routes.

As shown in the next image, Route D is selected (highlighted in yellow) for generating intersections. Since Routes AA, BB, CC, and DD intersect with Route D, locks need to be acquired for those routes. Since Route CC (highlighted in orange) cannot be locked by person B (because they're locked by person A or by person B in another version), intersections cannot be generated.

No intersections are generated as all locks are not available.

When conflict prevention is enabled, the following conditions are applicable to acquiring locks.

• If the tool runs on the default version, the locks acquired as a result of running this tool are released after a successful run.
• If the tool runs on a child version, the locks acquired as a result of running this tool are not released after a successful run.
• If the tool errors out or is stopped midway during a run, the locks acquired by the tool are released.

Scenarios for generating intersections

Intersection generation scenarios are detailed in the following sections.

Single intersections

In the following diagram and table, a single intersection is generated where three routes meet.

Route intersections are generated where routes meet.

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A and B and C	A,B,C	Network1		1/1/2000	<null>	5

An intersection generated or updated from the above scenario has the following characteristics:

• A single intersection is generated at the location where the three routes A, B, and C meet.
• The intersection name is determined by the sorting order of the route IDs.
• The route IDs are comma separated and alphabetically sorted.
• Feature ID is provided only for non-route-on-route intersections.
• The dates are determined by the common date range for all the routes that constitute the intersection.
• The measure is the measure of the first route in the route ID list at the location of the intersection.

Intersection time slicing

In the following diagram and table, an intersection is time sliced.

The intersections are time sliced.

Route A exists between dates 2010-<null>; Route B exists between dates 2000-2012 and Route C exists between dates 2020-<null>. The intersections are determined by the common date range for all the routes that constitute the intersection.

IntersectionID	Intersection name	RouteID	Feature class name	FeatureID	From date	To date	Measure
1	A and B	A,B	Network1		2010	2012	5
2	A and C	A,C	Network1		2020	<null>	5

An intersection time slice from the above scenario has the following characteristics:

• Between dates 2010-2012, only Route A and Route B existed, so an intersection (ID:1) is created for those dates between the two routes.
• Route B ceased to exist after 2012 and a new Route C comes to existence starting at 2020, so an intersection (ID:2) is created for between the dates 2020-<null> for Route A and Route C since that is the common date range between those two routes.

Multiple intersections

The following diagram and table detail the intersection of routes at more than one location.

The features intersect at more than one location.

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A and B	A,B	Network1		2000	<null>	2
2	A and B (2)	A,B	Network1		2000	<null>	8

In cases where the features intersect at more than one location, the intersection names have the suffix …(2), …(3), and so on.

Using z-values

In the following diagrams and tables, z-values are not used. In the second example, z-values are used.

Z-values are not used.

The following table shows the z-values at the point of intersection.

Z-values on routes

Route	Z-value
A	10
B	34
C	34

The outcome in the two following tables differs depending whether or not z-values are used in the intersection feature class.

When z-values are not used

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A and B and C	A,B,C	Network1		1/1/2000	<null>	5

When z-values are used

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	B and C	B,C	Network1		1/1/2000	<null>	24

Z-values are used to generate the intersections; therefore, Route B and Route C are participating in the intersection as their z-values (34 and 34) are within z-tolerance (0.001 m in this case). Route A with the z value of 10 is outside the z-tolerance.

Intersection ID is unique to every x,y,z location (when z-values are considered), or every x,y location (when z-values are not considered). If you have multiple intersections at one location (only possible due to presence of multiple time slices), all those intersections have the same Intersection ID.

Route and polygon intersections

The following diagram and table detail route and polygon intersections.

Route and polygon intersections use Feature ID.

IntersectionID	Intersectionname	RouteID	FCname	FeatureID	From date	To date	Measure
1	A and Poly1	A	Polygon1	Poly1	2000	<null>	2
2	A and Poly1 (2)	A	Polygon1	Poly1	2000	<null>	8

A route and polygon intersection from the above scenario has the following characteristics:

• These are the route and polygon intersections, so Feature ID is provided for them.
• The same route and polygon intersection name combination appears more than once, so the intersection names have the suffix …(2), …(3) and so on.

Scenarios for updating intersections

• When intersections are updated, the following situations can occur:
  • New intersections are created—New intersections can be created due to edit activities such as creating a route, realigning a route, extending a route, reassigning a route, cartographic realignment, or other edit activities including non-LRS features such as railroads or political boundaries.
  • Present intersections are retired—An intersection is retired with its ToDate field populated with the route's edit date due to realigning a route, retiring a route, reassigning a route, or other edit activities.
  • Present intersections are moved—Intersections are moved due to cartographic realignment or edits of non-LRS features. In such cases, that intersection's location is changed, and the shape (point location) for the intersection is updated, maintaining the intersection ID. The intersections are not retired in this case. If a feature intersects a route in multiple locations and the intersection locations change, the original intersection closest to the new location determines where the intersection is moved.
  • Present intersections are deleted—Intersections are deleted due to cartographic realignment or edits of non-LRS features. This occurs when the routes do not intersect the features anymore in any time range.

The following table details scenarios that can occur when updating intersections:

Edit activity	Route and route intersection	Route and non-LRS layer intersection
Route edits	Retires the present intersections or creates intersections	Retires the present intersections or creates intersections
Cartographic realignment: Intersecting as a result	Moves the present intersections or creates intersections	Moves the present intersections or creates intersections
Cartographic realignment: Not intersecting anymore	Deletes the present intersections	Deletes the present intersections
Non-LRS feature edited: Intersecting as a result	N/A	Moves the present intersections
Non-LRS feature edited: Not intersecting anymore	N/A	Deletes the present intersections

The following sections present examples of intersection updates.

Intersection updates when an intersecting feature is added

The following diagrams and tables detail intersection updates after a new intersecting feature is added.

An intersection exists between Route A and Route B.

An intersection exists between Route A and Route B.

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A,B	A,B	Network1		1/1/2000	1/1/2010	5

When Route C is created or appended, and it intersects Route A and Route B at the location of the original intersection, a new intersection with the same Intersection ID is created incorporating Route A, Route B, and Route C.

A new route, Route C, intersects at the same location.

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A,B	A,B	Network1		1/1/2000	1/1/2010	5
1	A,B,C	A,B,C	Network1		1/1/2010	<null>	5

Intersection updates when a route retires

The following diagrams and tables detail updates that occur after an intersecting route retires.

An intersection exists between Route A and Route B.

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A,B	A,B	Network1		1/1/2000	<null>	5

When part of Route B is retired, encompassing the location of the intersection, the intersection is retired with the to date of Route B.

The intersection is retired due to retirement of Route B.

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A,B	A,B	Network1		1/1/2000	12/31/2020	5

Intersection updates after cartographic realignment

The following diagrams and tables detail updates that occur after part of Route B is cartographically realigned.

The location of the intersection is updated along with the measure where the new intersection is located along Route A. In cases where Route B is cartographically realigned and no longer intersects with Route A, the intersection is deleted.

An intersection exists between Route A and Route B.

Intersection ID	Intersection name	Route ID	Feature class name	Feature ID	From date	To date	Measure
1	A,B	A,B	Network1		1/1/2000	<null>	5

Route B is Cartorealigned.

Intersection ID	Intersection name	Route ID	FC name	Feature ID	From date	To date	Measure
1	A,B	A,B	Network1		1/1/2000	<null>	3