RULE-BASED OBJECT-ORIENTED MODELLING OF PUBLIC TRANSPORT SYSTEMS

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RULE-BASED OBJECT-ORIENTED MODELLING OF PUBLIC
TRANSPORT SYSTEMS

• Otto Anker Nielsen (oan_at_ctt.dtu.dk)
• Research Professor, Ph.D.
• Centre for Traffic and Transport
• Technical University of Denmark

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The Presentation

• The project
• Background
• Object oriented approaches
• The data model
• Elements of the Transport Object Platform
• Examples
• Utilising TOP in transit assignment procedures
• Advantages / summary

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The project

• Internally funded development project
• Developed in cooperation between WS Atkins, the
  Technical University of Denmark and ESRI
• Aim Making it possible to handle complex,
  multi-modal transportation data in a GIS
• On top of that Advanced analysis and modelling
  tools

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Background
Research (BRIDGES)
Practical Experience (CRM)
TOP
Research (SPOTLIGHT)
Technology Available (ArcGIS)
Market Opportunity
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Typical problems in prior GIS
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Background East Denmark Model (CRM)

• A detailed traffic model covering half of Denmark
• Timetables (all runs with about 2,500 lines 0.4
  mio. stops, 30,000 stop groups and 4 mio. pseudo
  arcs)

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Background - CRM

• Complex dataflow, Difficult to maintain
  consistency
• Separate models used proprietary data formats

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Background - Technology

• Newest generation of GIS is
• Object Oriented
• Flexible - new and customisable data models, etc.
• Extensible Programmable - embedded
  functionality
• Open - Standard DBMS, COM, VBA etc.
• Offers advanced features - tools, versioned
  editing etc.
• It is now possible to create new topological
  objects,
• design new data models and embed functionality!

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Object oriented approaches (1)

• Objects encapsulates
• Properties
• Functionalities
• Events

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Object oriented approaches (2)

• Objects can
• Inherit properties and functionalities
• Be grouped together (within or between classes)
• Be related to each other (within or between
  classes)
• In ArcInfo they can also follow connectivity
  rules to each other

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The Transport Object Platform consists of

• Conceptual model
• Data model
• Programmed functionality in data objects
• Editing and Visualization tools
• Advanced modelling and analysis tools

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Data model (1)
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Data model (2)
TOP Conceptual Overview
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Data model (3)
TOP Conceptual Overview
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Data model (4)
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Data model (5)
ESRI Classes
SimpleJunctionFeature
ESRI Classes
Feature
ESRI Classes
SimpleEdgeFeature
ESRI Classes
Object
ChangeEdge
Connector
DEMAND
Terminator
Turn
TransportEdge
Matrix
MatrixElement
TransportJunction
PHYSICAL
Run
RelationshipClass
ROUTE
NETWORK
StopEdge
RouteSegmentDetail
NETWORK
RelationshipClass
RouteDetail
FrequencyRun
Route
Stop
RouteSegment
StopJunction
RelationshipClass
Terminals
TimePatternDetail
TimePattern
DiscreteRun
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Stops
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A Road Network
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Stops are added, they automatically connect to
the roads
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Draw bus routes by clicking near StopJunctions,
where the bus stops and near roads to
guide the bus
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The Route automatically swaps to the road
network, builds relationships to the roads and
creates Timepatterns
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A road is modified
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and the Route changes. Drivingtime in the
TimePatterns is likewise changed
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Grab a Stop and move it
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The Stop triggers move of the StopJunction,
which in turn shortens the Route and
changes TimePatterns.
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Modifying a road with Stops
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will modify the Route and TimePatterns and move
the StopJunctions, but leave the Stops
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Moving a road and rubberbanding..
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also changes Routes and StopJunctions and
TimePatterns
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In addition complex scheduling data like these
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..can be presented in 3D.
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Utilising TOP in Public transport assignment
models

• Different conceptual levels of networks
• Geographic network
• Organisational network
• Calculation network (logical network, not only a
  graph)

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Multi-modal modelling extracting the logical
network from TOP
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Rule based assignment models

• The graph is built dynamically (graph pruning)
• Search algorithms utilise the hierarchical
  structure of the network
• Á priori knowledge and geographical information
  can be used in label correction methods
• Refer to paper at TRISTAN IV

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Advantages and summary

• GIS Environment is easy to use intuitive
• Open, Extensible Programmable
• Handles multiple layers of data, maintains
  consistency
• By using consistent and detailed data, better and
  faster models can be implemented
• Cut data-handling efforts significantly
• Facilitate work with more detailed data