Event behaviors

Roads and Highways keeps event measures in alignment with LRS route edits. You can configure event behavior rules to define how event measures are updated for each type of route edit.

What is event behavior?

Events are located along a route in a linear referencing system (LRS) using a location reference (for example, measure distance down a route). Because location is based on the highway length, changes in the length have a direct impact on how the events will be located and how they are rendered on a map. The impact of the changes to the route have on events is called event behavior.

Roads and Highways supports multiple ways to locate your event on a route, such as measure on route, reference offset from intersection, stations, feature offsets, offset from another event, or x,y coordinates.

Below is an example of a route being realigned. This route has a line event and a point event located along the route. After a route is edited, the events are updated using the event behavior rules.

Types of event behavior rules

When an LRS route is edited, behavior rules are applied to the events. By providing the event behavior rules, you decide what the event does when the route changes: preserve location, preserve measure, or maintain referent location.

Event behavior rules	Description
Stay Put	Preserves the geographic location of the event; measures may change.
Move	Preserves the measure(s) of the event; geographic location may change.
Retire	Preserves both measure and geographic location; event is retired.
Snap	Preserves the location of an event by snapping the event to a concurrent route; measure(s) may change.

Stay Put

The Stay Put rule preserves the geographic location of the event. When the route is modified, events retain their x,y coordinates. This means event measures will change whenever it is necessary to retain the location.

With Stay Put event behavior, events downstream of an edit section retain the location. The line events that intersect the edit section will be split into two or more events, so the portion not affected by the route edit will retain its location. Events that are completely contained within the edit section are retired.

In the above example, the upstream events that did not intersect the realignment did not change. The line event that spans the realignment section gets split into two parts, and the original event is retired. The point event that falls inside the realignment section is retired. The downstream events retain the x,y location.

The table below shows how the Stay Put event behavior updates events for each edit activity.

Activity	Events upstream	Events within edit section	Events downstream
Extend Route	No action	Shape regenerated.	Measure(s) adjusted to retain x,y if recalibrate downstream selected as an option
Calibrate Route, Reverse Route	Measure(s) adjusted to retain x,y	Measure(s) adjusted to retain x,y.	Measure(s) adjusted to retain x,y
Realign Route, Realign Overlapping Route	Up to closest upstream calibration point; measure(s) adjusted to retain x,y if needed	Retire event; line events crossing edit section will be split and original event retired.	Measure(s) adjusted to retain x,y if recalibrate downstream selected as an option
Retire Route, Reassign Route	No action	Retire event; line events crossing edit section will be split and original event retired.	Measure(s) adjusted to retain x,y if recalibrate downstream selected as an option

Move

The Move rule preserves the measure(s) of the event. When a route is modified, events retain their measure values. This means x,y coordinates may change.

For example, with Move event behavior, events downstream of a realignment retain the measure, although the location along the route changes.

In the above example, events in the realignment section and downstream preserve the measures and their shape is updated per the new route shape.

The table below shows how the Move event behavior updates events for each edit activity.

Activity	Events upstream	Events within edit section	Events downstream
Extend Route	No action	Shape regenerated	Shape regenerated if recalibrate downstream selected as an option
Calibrate Route, Reverse Route	Shape regenerated if needed	Shape regenerated	Shape regenerated if needed
Realign Route, Realign Overlapping Route, Retire Route, or Reassign Route	Shape regenerated if needed	Shape regenerated	Shape regenerated if recalibrate downstream selected as an option

Retire

The Retire event behavior preserves both measure and location. When you modify a route, the system flags the event as retired by changing its To Date value to the effective date of the edit if the event is in an impacted region of the route.

The event's measure(s) does not change, but the event will no longer be displayed in the current alignment of the highway. If you want to see the event, you must set the event layer's temporal view date (TVD) to a date and time prior to the edit.

For more information about changing the time view, see Setting the time view for LRS data.

In the above example, the upstream events, where retaining the measure and location was possible, did not change. The line events that fall in the realignment section completely or partially are retired. The point event that falls inside the realignment section is retired. The downstream events are retired as well.

The table below shows how the Retire event behavior updates events for each edit activity.

Activity	Events upstream	Events within edit section	Events downstream
Extend Route	No action.	Retire event.	Retire event if recalibrate downstream is selected as an option.
Calibrate Route, Reverse Route	Retire event.	Retire event.	Retire event.
Realign Route, Realign Overlapping Route	Up to closest upstream calibration point; retire event if needed.	Retire event; line events crossing edit section will not be split.	Retire event if recalibrate downstream is selected as an option.
Retire Route, Reassign Route	No action.	Retire event; line events crossing edit section will not be split.	Retire event if recalibrate downstream is selected as an option.

Snap

The Snap event behavior preserves the location of an event by snapping the event to a concurrent route. When the route being edited is concurrent with another route, you may want the event to snap to the concurrent route that is not being edited. You can choose the dominant route during the edit, or you can automate it by setting up the route dominance rule.

For more information about route dominance, see Configuring route dominance.

This rule is applied only to Realign Concurrent or Overlapping Route, Reassign Route, and Retire Route edit activity.

In the above example, there is a concurrent route named B. The line event that spans the realignment section is split into three parts. The part that falls exactly in the realigned section is snapped to the concurrent route B. The point event that falls inside the realignment section is snapped to the concurrent route B. Events that are snapped retain their locations but get updated route references and measure(s). The last portion of the diagram shows that route A and route B are conceptually separated, to demonstrate how events are snapped to the concurrent route.

Events or event portions that were outside the realignment retain their locations as they did with the Stay Put event behavior rule.

The table below shows how the Snap event behavior updates events for each edit activity.

Activity	Event upstream	Event within edit section	Event downstream
Realign Overlapping Route	Up to closest upstream calibration point, measure(s) adjusted to retain x,y, if needed	Geographic location maintained. If no concurrent route, event will stay put. If there are concurrent route(s), event will be migrated to the dominant route. Line events crossing the edit section will be split.	Measure adjusted to retain x,y if recalibrate downstream selected as an option
Reassign Route, Retire Route	No action	Geographic location maintained. If no concurrent route, event will stay put. If there are concurrent route(s), event will be migrated to the dominant route. Line events crossing the edit section will be split.	Measure adjusted to retain x,y if recalibrate downstream selected as an option

When performing a cartographic realignment, there are two options: Honor Route Measure or Honor Referent Location. These rules apply only to cartographic realignment edit activity.

For more information about cartographic realignment, see Cartographic realignment.

Event behavior rules	Description
Honor Route Measure	Try to preserve the measure of the event; event measure may change proportionally to the route measure change.
Honor Referent Location	Maintain the referent location of the event.

Honor Route Measure

The Honor Route Measure rule tries to preserve the measure of the event.

You can configure a property on the LRS Network Properties dialog box to update route length and recalibrate route based on change in geometry length.

For more information about this setting, see Creating an LRS Network.

If this property is selected, the event measure changes proportionally to the measure change of the route, and the event shape will be updated to align with route.

In the above example, since you have the Update route length property selected, the line event's to measure is updated proportionally, and the point event's measure is also updated proportionally. The event's shape is updated to align with the route. This also applies the Calibrate Route event behavior to the section of the route that is recalibrated.

If this property is not selected, the event will preserve its measure and the event shape will be updated to align with route.

In the above example, since you do not have the Update route length property selected, event shapes are updated to align with the route.

Honor Referent Location

The Honor Referent Location rule maintains the referent location of the event. This rule is applied only when you have an event configured to store referent locations.

For more information about reference offset events, see Storing referent and offset information for event location.

Note:

If the referent is not valid or not present during event behavior processing, the event's measures are used to regenerate the event shape.

In the above example, the line event's from measure is referenced from Intersection 1, and its to measure is referenced from Intersection 2. The point event is referenced from Intersection 2. After cartographic realignment, the event measure is updated to maintain the referent location, and the event's shape is updated to align with the route.

Factors to consider

In addition to the above event behavior rules, there are a few other factors to consider to completely understand event behavior.

Do not apply measure behaviors

During the route editing, you can choose not to apply any of the above event behaviors.

If this is chosen, none of the above behavior is applied, but event shapes are regenerated to align with the route.

Recalibrate Downstream

Route edits affect the calibration of the route, and during the edit activity, the Roads and Highways dialog box may ask you if you want to recalibrate downstream.

As shown in the above example, there are calibration points at measures 0, 50, and 80. You can choose to recalibrate downstream during realign activity. This will update the calibration of the route after the calibration point at measure 50 until the end of the route.

Due to recalibration, the event behavior is applied to the recalibrated section per the rule you set for Calibrate Route.

How to apply event behavior

Event layers are either internal, meaning they reside within the geodatabase that contains your ALRS, or external, which means they reside outside of the geodatabase that contains your ALRS.

For more information about event types, see Event types.

Internal events

Internal events can have event behavior applied after each edit or a series of edits using the Apply Updates tool on the Roads And Highways Editing toolbar. If you do not use the Apply Updates tool and try to save the edits, event behavior is applied by Roads and Highways just before edits are saved. This is to make sure the events are always in alignment with route edits.

Note:

Invoke event behavior using the Apply Updates tool before you reconcile and post in the edit session.

External events

External events do not have event behavior applied during a route edit. You can apply event behavior to external events using the Relocate Events geoprocessing tool.

For more information about Relocate Events, see Relocate Events.

Configuring the event behavior rules

Event behavior is configured when you register events with the LRS Network. You can also reconfigure event behavior at any time by opening the event layer's properties.

During the process of registering events through the ALRS Event Setup wizard, you can set event behavior rules for each type of activity applied to the route.

Note:

Event behavior rules are not applied to X and Y offset events, Offset from an Event, and Offset from a Point Feature Class.

For more information about registering an event, see Registering an event by Route and Measure and Registering an external event source.