Network Creation from LRS
Process Diagram
Data
| Data Name | Data Location | Purpose |
|---|---|---|
| SubBlock Intersections | SubBlock Intersections are point features representing all At-Grade intersections. | |
| SubBlock | SubBlocks are polyline features created between two intersections of any road type. These are our smallest unit of roadways. | |
| Block Intersections | Block Intersections are point features representing all At-Grade street-type intersections (intersections with alleys/driveways/trails/etc. excluded) | |
| Block | Blocks are polyline features created between two street-intersections and are only street type roadways. | |
| Intersection Approaches | Intersection Approaches are polyline features that represent each 'leg' (intersecting route) of an intersection, up to 10 meters in length. | |
| Bike Lanes | ||
| Sidewalks | ||
| Total Road Width | ||
| Speed Limits | ||
| Turn Lanes |
Network Dataset creation
- Network dataset created in file geodatabase (H:\GIS\Data\Network_Dataset)
- Edges - SubBlock feature class
- Junctions - SubBlockIntersection feature class
- Junction point created at each end of an edge (includes dead ends)
- Junction point created at each end of an edge (includes dead ends)
- Created "Oneway" attribute in SubBlock to code one-way (digitizing and non-digitizing direction) and two-way streets.
- Use SA to reference section data and create updated oneway attribute?
- Perhaps look into custom attributes/evaluators,
Approach Data for Turn Features
- Capturing Turn Data: Script created to extract cross-section data, but still needs some work. Script is in Automation/Network Analysis folder: GenerateApproachTurnData
- Creates an easy-to-use reference table that allows Osheen's script to get what allowable turns are there.
- Approaching direction only
- Like this:
IntersectionID ApproachID LeftAllowed RightAllowed ThroughAllowed 123 ABC 1 1 1 456 DEF 0 0 1
Segment Data for Network Dataset
- Capturing roadway attributes: Script (still needs to be written) to extract relevant data for each road edge.
- Each network edge must have attributes in order to provide real-world factors for analysis. These factors are listed below and are also in the diagram above:
- Bike Lanes
- Sidewalks
- Speed limits
- Total roadway width
Turn Table for Network Dataset
- Comprehensive table where each row represents a potential turn (no restrictions present)
- Contains route/subblock/approach/intersection information for both edges of turn, and also displays the turn direction, and turn angle.
- Non-At Grade intersections are omitted, since they don't play a factor into turns.
Turn Features for Network Dataset
- Table where each row represents an actual (permissive) turn you can make