Create the LRS, networks, events, and intersections

Disponible avec la licence Location Referencing.

The following information guides you through the process of linear referenced data modeling, loading, and route editing using the ArcGIS Roads and Highways extension.

LRS dataset

A linear referencing system (LRS) dataset is a feature dataset containing all the LRS feature classes.

Remarque :

You can view the LRS hierarchy from either the Contents or Catalog panes.

Remarque :

The LRS dataset is visible only in ArcGIS Pro. An error message appears if a geodatabase that contains the LRS dataset is opened in ArcMap.

The following tools create an LRS dataset, as of ArcGIS Pro 2.3:

• Create LRS—The newly created centerline, calibration point, and redline feature classes are placed inside a feature dataset with the same name as the provided LRS name.
• Create LRS From Existing Dataset—The existing centerline, calibration point, and redline feature classes that are not yet registered with an LRS must be inside a common feature dataset. The feature dataset name can be different from the LRS name.
• Modify LRS—The existing centerline, calibration point, and redline feature classes that are registered with an LRS must be inside a common feature dataset. The feature dataset name can be different from the LRS name.

The LRS dataset is required to run the following tools:

• All Configuration toolset tools
• Append Events
• Append Routes
• Apply Event Behaviors
• Delete Routes
• Derive Event Measures
• Generate Calibration Points
• Generate Events
• Generate Intersections
• Generate Routes
• Remove Overlapping Centerlines

You can read some of the information contained in the LRS dataset using an arcpy.Describe function. To read the LRS Metadata and Event Behavior Rules for a geodatabase with an LRS controller dataset, use the following functions:

FileGDB:

desc = arcpy.Describe("C:\\Data\\LRData\\LrsSchema.gdb\\Lrs\\Lrs")

lrsXML = desc.lrsMetadata

eventBehaviors = desc.eventBehaviorRules

EnterpriseGDB:

desc = arcpy.Describe("C:\\Data\\LRData\\LrsSchema.sde\\GPRefresh.DBO.LRS\\GPRefresh.DBO.LRS")

lrsXML = desc.lrsMetadata

eventBehaviors = desc.eventBehaviorRules

Writing to a file:

txtFile = open("C:\\Data\\LRData\\lrsXML.xml", "w")

txtFile.write(lrsXML)

txtFile.close()

Data modeling

Transportation professionals are routinely tasked with considering alternative routing options to ensure regulatory compliance, market, construction, and other business needs. This usually results in realigning (rerouting) a roadway. Realignment not only changes the pathways of roads, but also impacts networks and events configured in an LRS data model.

To use Roads and Highways, your data needs to be in the Roads and Highways information model in the geodatabase. For more information, refer to the following topics:

• LRS data model
• Tolerance and resolution settings for the LRS
• Events data model

LRS configuration

The modeling and creation of your linear referencing system (LRS) can be performed using the following tools.

1. Create and modify an LRS.

   You can use either the Create LRS or Create LRS From Existing Dataset tool to create an LRS.

   To modify an existing LRS, use Modify LRS. This includes enabling conflict prevention in an LRS.

   Learn more about how to create and modify an LRS

2. Create LRS networks.

   You can use either the Create LRS Network or Create LRS Network From Existing Dataset tool.

   To modify an existing LRS Network, use the Modify LRS Network tool.

   Learn more about how to create and modify an LRS Network

3. Create LRS events.

   You can use either the Create LRS Event or Create LRS From Existing Dataset tool.

   To add referent fields to the event feature class, use Enable Referent Fields. This tool enables the referent fields by allowing you to register existing fields as referent fields.

   To modify an existing LRS event, use Modify LRS Event.

   Learn more about how to create and modify LRS events

4. Create LRS intersections.

   You can use either the Create LRS Intersection or Create LRS Intersection From Existing Dataset tool.

   To add intersections to your intersection feature class, run Generate Intersections.

   To modify an existing LRS intersection feature class, use Modify LRS Intersection.

   Learn more about how to create and modify LRS intersections

5. Load routes into the LRS Network.

   Once the LRS is created, routes can be loaded using the Append Routes tool. Route shapes can be regenerated using the Generate Routes tool.

   Learn more about how to load routes into an existing LRS Network

   Learn more about setting gap calibration rules for your LRS Network

6. Create calibration points.

   To add calibration points, use the Generate Calibration Points and Append Routes tools.

7. Prepare centerlines

   To remove overlaps that could cause data errors, use Remove Overlapping Centerlines.

8. Load event data.

   To load event records from a table, layer, or feature class into an existing event feature class, use Append Events.

   Learn more about how to create and modify LRS Events

Realign and reroute

The following list is offered as process guidance for the tools required for realigning (rerouting) and maintaining linear referenced data:

• Create Centerline—Determine if one or more centerlines exist for the realignment portion of a route or routes.
• Event Behavior—Consider how event behavior rules can apply to your route edits.
• Apply Event Behaviors—Apply event behaviors to keep event measures in alignment with route edits.
• LRS Network—Determine if other LRS networks are affected by route edits.
• Generate Routes—Regenerate shapes for LRS networks.

Route editing workflows

Similar workflows can be created for other route editing activities such as create, extend, realign, reassign, retire, calibrate, and cartographic realignment.

The following table and list can be used as recommendations or guidance for processes and functions required for editing and maintaining roadway data.

Route edit activity table

Step	Workflow	Create	Calibrate	Cartographic Realignment	Extend	Realign	Reassign	Retire
1	Create a centerline.	Y	N	N	Y	N	N	N
2	Perform the editing activity.	Y	N/A	N/A	Y	Y	Y	Y
3	Run the Apply Event Behaviors tool.	N	Y	Y	Y	Y	Y	Y

If additional LRS networks are configured, repeat the edit activity for each affected network.