Download TAC Slides (May) - Travel Modelling Group

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TRAVEL MODELLING GROUP
TECHNICAL ADVISORY COMMITTEE
May 8, 2013
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Today’s Agenda
• Overview of current TMG tools & available resources
• TMG Toolbox
• EMME worksheets
• XTMF
• Getting / installing TMG tools
• Requirements
• Obstacles?
• Centroid Connector Generation
• TMG Website (tmg.utoronto.ca)
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Current Tools: TMG Toolbox
• Suite of Tools for Emme Modeller
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Current Tools: TMG Toolbox
Currently contains tools for:
• Results Analysis
• Validation/Conversion with/to NCS11
• Network editing including Centroid Connectors
• XTMF-compatible road and transit assignment scripts
(converted from original macros)
• Python libraries for some common code
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Current Tools: TMG Toolbox
NCS11
• A number of tools to facilitate conversion
Network Editing -> Centroid Connectors
• For detailed discussion later
• “Copy Zone System” tool for porting centroids +
connectors from one databank to another. Produces a
shapefile illustrating connectors not copied.
Network Editing -> Transit Networks
• “Create Time Period Networks” will be used to generate
transit networks for multiple time periods
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Current Tools: TMG Toolbox
Assignment Tools
• Robust, generic ports of major assignment macros for use
from Modeller or XTMF
• Matrices, scenarios, and attributes no longer are hardcoded
• Results saved into user-specified matrices
• Transit assignment split into separate assignment and
analysis tools / modules
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Current Tools: TMG Toolbox
Analysis -> Screenlines:
• Allows screenlines to be
defined by shapefiles
• Can be “imported” into the
network as extra attributes,
or used to extract results
“on-the-fly”
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Current Tools: TMG Toolbox
Scripting tools:
• “Execute Python Script” Tool permits the execution of
single script files (*.py), with all ‘print’ statements echoed
to the logbook.
• The “Geometry” library contains functions for integrating
Emme networks with geometric operations.
• “Screenline” library is the basis of all screenline tools; can
also be used for scripting.
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Current Tools: Emme Worksheets
• Transit line viewer
• NCS11 VDF Viewer
• NCS11 Node Viewer
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Current Tools: XTMF
• Capabilities:
• Four-step models
• Network parameter estimation
• Mode choice parameter estimation
• Network connector optimization
• Population synthesis
• New features:
• Linked Parameters
• Integrated documentation
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Software/Hardware Requirments
TMG Toolbox:
• Emme Modeller
XTMF:
• Windows XP or newer
• .NET framework version 4.0 or higher.
• GPU requirements (optional): DirectX 11 graphics card
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Centroid Connectors
• Objective: Create an algorithm for generating centroid
connectors for a given network and a given zone system
• Challenges:
• Easy to define and apply hard constraints, but difficult to define an
objective function
• Cannot reasonably assume that zone internal roads are not present
(especially when applying an older zone system to a newer
network)
• Not much experience to draw upon in the literature
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Algorithm Framework
• Apply well-defined constraints to the network’s nodes to
prevent unrealistic connections (e.g., to highway on- and
off-ramps).
• Choose from a set of possible centroid connector
configurations.
• Avoid an algorithm in which processing order matters by
avoiding constraints which depend on the connections
made by other zones.
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Algorithm Framework
• Feasible Nodes: The set of nodes in the network for which
a centroid connection is feasible.
• Candidate Nodes: The set of nodes which are candidates
for connection to a given zone centroid.
• Configuration: A selected sub-set of a zone’s candidate
nodes which represents a potential configuration of
connectors.
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Proposed CCGEN steps
For all zones
1. Create the set of feasible network nodes by applying a userspecified criteria.
For each zone
1. Get the set of candidate nodes by searching the set of
feasible nodes (usually based on distance).
2. Reduce the set of candidate nodes which result in
connectors which cross user-specified boundaries.
3. Reduce the set of candidate nodes to the user-speicifed limit
by removing the furthest nodes first.
4. Iterate through all of the potential combinations of centroid
connectors, from one connection up to a user-specified
maximum, and calculate a utility value for each.
5. Create connectors for the combination with the highest
utility.
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CCGEN Utility Function
What is a ‘good’ configuration of centroid connectors? What
makes one configuration ‘better’ than another?
• Some ideas:
• Try to distribute the connectors radially around the centroid.
• Try to prioritize certain nodes (i.e., mid-block nodes, or nodes very
close to the centroid).
• Others…?
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TMG Website
http://tmg.utoronto.ca
• All TMG TAC and SC members already have accounts.
• Your account is “[First Name] [Last Name]”, and the
default password is “ChangePassword” (case-sensitive)