340 likes | 378 Views
Using GIS Networks to Represent Model Networks. May 19, 2009 Hoyt Davis & Chunyu Lu Gannett Fleming, Inc. Outline. Background Introduction. Generating True Shape Networks in Travel Forecast Model. Incorporate Into Cube Environment. New Technology. Questions?. Background Introduction.
E N D
Using GIS Networks to Represent Model Networks May 19, 2009 Hoyt Davis & Chunyu Lu Gannett Fleming, Inc.
Outline • Background Introduction • Generating True Shape Networks in Travel Forecast Model • Incorporate Into Cube Environment • New Technology • Questions?
Background Introduction • Former Florida highway model networks were generally “stick-figured” networks that show traffic flows from one node point to another using straight lines. • The “stick-figured” networks usually: • Do not have to represent the highway network in a visually pleasing way; • Are commonly modified to allow some roadway curvature by breaking their network links into smaller pieces; • Do not incorporate full functionality from ArcGIS Engine and Geodatabase; • Make the highway network less efficient causing longer model processing times. • The latest versions of Cube Voyager allow users to utilize true shape networks which use GIS detail accuracy in its integrated network environment.
Background Introduction • FDOT District 7 and District 5 have requested for Gannett Fleming to develop GIS-based highway networks for initial use in their Regional Planning Models. • The new GIS-based network is expected to: • Improve the accuracy of the model in terms of truer GIS distances of highway facilities; • Decrease the number of highway links in the model networks and therefore decrease the model processing times; • Incorporate full functionality of the ArcGIS Engine and Geodatabase technology; • Provide for better integration with future versions of the Cube Voyager software.
Outline • Background Introduction • Generating True Shape Networks in Travel Forecast Model • Incorporate Into Cube Environment • New Technology • Q&A
How Did We Get Started… • Available data resources: • State TeleAtlas/GDT roadway data • Aerial photos • Existing model networks • There are two options to get started: • Start with available non-transportation base true shape GIS networks to clean network attributes and merge links; or • Start with existing model networks and realign network links based on true shape curvatures from true shape GIS networks. • It was more efficient to start from the model networks and manually realign the network to true shape curvatures.
Challenges • #1: Consolidate the network from small link pieces; • #2: Manually match every vertex to the true shape curve; • #3: Incorporate the true shape network into the Cube environment and the model flow seamlessly. Solutions: • Link consolidation based on area type, facility type, and number of lane combination; • Link conflation tool developed using Visual Basic for Applications in the ArcGIS Environment; • “Build Network from Shape File” Tool and Cube script.
Other Challenges • Coordinate with the Department and the MPOs to determine all improvements to the highway system between existing network and the new base year network. • More network attributes were required to be added: • Posted Speed • Count Sources and Count Station ID • Local /MPO/ County Screenlines • Highway network support file development included: • Toll link file • Time penalty and turn prohibitor file • Transit station file • Use Cube scripting to develop a process to convert the GIS network shape file to a model network.
Geometry Conflation Tool Target: GDT Layer Model Network
Geometry Conflation Link Match Node Match
New Roadway Attributes • Road Name and Alternative Road Name • Posted Speed • Traffic Count Sources and Station ID • Local/County/MPO Screenlines • Roadway Label and Number • Federal Functional Classification code
Highway Links and Nodes by County • The true shape network means new features: • Specify external and dummy centroids • Node renumbering by County • Node number sorted by X and Y coordinates • Highway links and centroid connectors summary by County
Outline • Background Introduction • Generating True Shape Networks in Travel Forecast Model • Incorporate Into Cube Environment • New Technology • Q&A
Edit Highway Links in Cube • Add Highway Links • Copy links attributes • Update node number • Move Links • Node snapping • Update node number • Link direction • Delete Links • Link Split
Outline • Background Introduction • Generating True Shape Networks in Travel Forecast Model • Incorporate Into Cube Environment • New Technology • Q&A
Outline • Background Introduction • Generating True Shape Networks in Travel Forecast Model • Incorporate Into Cube Environment • New Technology • Q&A