Essential Roads and Highways vocabulary

Activity

Often used in the context of edit activities, which are discrete capabilities supported by Roads and Highways for Desktop to edit LRS Networks. Roads and Highways for Desktop supports the following edit activities: create route, extend route, realign route, cartographic realignment of route, reassign route, reverse route, and retire route.

ALRS

Acronym for the Advanced Linear Referencing System, a linear referencing system implemented by Roads and Highways on the ArcGIS platform that supports multiple linear referencing methods and event measure behaviors.

Asset

In the context of linear referencing, often refers to a type of linear referenced event that represents a physical object, such as a sign, guardrail, or bridge.

Calibration point

A point feature that defines the measure for a specific location on an LRS route. Roads and Highways uses calibration points to define the measures on the routes. The measures between two calibration points on a route are derived by linear interpolation.

Centerline

A polyline feature that defines part (or all) of the geometry of an LRS route. Routes in Roads and Highways can share centerlines in the same network (as is the case for concurrent, overlapping, or common routes) or routes in separate networks.

Conflict prevention

Functionality in Roads and Highways for Desktop that improves support for a multiuser enterprise geodatabase LRS Network and event editing by coordinating route and event edits.

Event

In the context of linear referencing, refers to data that is located by its association to an LRS route and measure location. There are two event types. Point events have a single measure along a route while linear events have a from and to measure along a route. Events are typically modeled in a database with a column for the route ID the record references, a measure column for the location on the route (two measure columns if it's a linear event), and a value (like speed limit). Additional temporal information on the time frames the event is valid can also be modeled.

An example of a point event is a crash location referenced to route Interstate 10 that occurred 10.53 miles down the highway. An example of a linear event is the record of a speed limit of 65 MPH on Interstate 10 from 0 miles to 20.5 miles.

Event behavior

In the context of linear referencing and Roads and Highways, event behavior refers to the configuration that defines how event measures and route associations respond to changes or edits in the LRS Network.

Roads and Highways, based on network edits, supports the following event behaviors:

• Stay Put: Keeps events geographically fixed in a location, which may result in event measures changing on modified portions of routes
• Snap: Reassigns (or snaps) events to dominant routes on modified portions of routes
• Move: Keeps event measures fixed, which may result in events geographically moving on modified portions of routes
• Retire: Retires events on portions of routes that change

Event lock

Event locks are a capability in Roads and Highways for Desktop conflict prevention that allow a user to prevent other users from editing events for an event layer on a specific route. When events for an event layer on a route are locked, only the user with the lock can edit those events on the route in the version the lock was acquired. Other users can acquire event locks for the same route on a different event layer, if needed. To acquire an event lock, a user must first reconcile with the lock root version. To release an event lock, the user needs to post changes to the locked events to the lock root version. If any event locks exist for a route, no users can edit the route until all event locks are released.

External event

Linear or point events that reside outside the geodatabase where the ALRS is configured. When registered, Roads and Highways creates a read-only connection to the source data to create an event feature layer using the source table as the authoritative source.

External system

Databases and other data storage systems of event data that are outside the management of Roads and Highways. These systems can contain event data that is based on a different LRM and may not be spatial in nature.

Internal event

Linear of point events that reside inside the geodatabase where the ALRS is configured. When registered, Roads and Highways creates an event feature class and manages the shape of the feature based on the route, measure, and to and from dates.

Interpolative LRM

A linear referencing method that determines a location by interpolating between two known measures.

Linear network maintainer

GIS analyst responsible for editing the ALRS.

Linear event

An event that represents a segment of a route from a starting measure (or from measure) to an ending measure (or to measure).

Lock root version

The lock root version is a named enterprise geodatabase version that is used by users as the common ancestor version in Roads and Highways conflict prevention to reconcile with in order to acquire route and event locks. It is also the version that users must post to in order to release route and event locks for routes and events that were edited. The lock route version can be configured in the ALRS properties Enabling conflict prevention in the ALRS to be the DEFAULT version or a surrogate to the DEFAULT version.

LRM

Acronym for linear referencing method, a method for defining measurements along linear features for the purpose of linear referencing. Examples of LRMs are State Mile Point, County Mile Point, or Project Stationing.

LRS

Acronym for linear referencing system, the method of storing geographic locations by using relative positions along a measured linear feature.

LRS Network

A collection of routes, measured to a specific LRM in Roads and Highways.

Measure

A location along a route based on a distance from a known point of origin.

Point event

An event that represents a single point location on a route at a specific measure.

Project stationing

A system of stationing in which the starting reference station is established at the base of a project location, and all distances along the route centerline are measured from that point location.

RCE

Acronym for Roadway Characteristics Editor, the web based event editing application included with Roads and Highways for Server.

Redline

A feature in Roads and Highways that can be added to the redline feature class and can be used to communicate desired modifications to the LRS Network. The Roads And Highways Editing toolbar accepts redlines as input into the various network editing activities.

Referent

A fixed location along a route that has a discrete measure value from which other locations are determined.

Referent offset

A fixed distance from a referent; can be positive or negative.

Referent offset event

An event whose location is modeled as being a specific distance along a route relative to another event on the route.

Route

A linear LRS feature.

Route lock

Route locks are a capability in Roads and Highways conflict prevention that allow a user to prevent other users from editing a route and events on a route while the route is being edited. When a route is locked, only the user with the lock can edit the route and events on the route in the version the lock was acquired. To acquire a lock on a route, a user must first reconcile with the lock root version. To release a lock on a route, a user needs to post changes to the route and events on the route to the lock root version.

Station

Reference points that are placed along the horizontal measurement of a route, centerline, or baseline at a regular interval. Station numbers increase from West to East or South to North based on the cardinal direction of the overall highway

Stationing

The fundamental system of measurement used by surveyors. For highway projects, a starting reference station is first established and then all distances along the route centerline are measured from that point location. Generally, the distance between two adjoining stations along a route is 100 feet. The first station located at the beginning of the baseline is 0+00 and the next station located 100 feet away from it is 1+00. Therefore, a station number of 10+34.05 depicts 1034.05 feet (10*100 + 34.05) away from the starting station.