RULE-BASED OBJECT-ORIENTED MODELLING OF PUBLIC TRANSPORT SYSTEMS

RULE-BASED OBJECT-ORIENTED MODELLING OF PUBLIC TRANSPORT SYSTEMS

Centre for Traffic and Transport (CTT), Technical University of Denmark (DTU)

RULE-BASED OBJECT-ORIENTED MODELLING OF

PUBLIC TRANSPORT SYSTEMS

Otto Anker Nielsen ([email protected])

Research Professor, Ph.D.

Centre for Traffic and Transport

Technical University of Denmark



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



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



Background

TOP

Market Opportunity

Research (BRIDGES)

Technology Available(ArcGIS)

Practical Experience

(CRM)

Research (SPOTLIGHT)



Typical problems in prior GIS

a) Network represen-tatiton by pseudo links and nodes whicheach are digitised

Line a,b Line a

Line b, c

Line c

Network withbusroutes:

Line a Line aLine a Line a

Line b

Line b

Line b

Line b

Line c

Line c

Line cLine c

Line aLine a Line a

Line b

Line b

Line b

Line c

Line c

Line cLine c

b) Network represen-tation with turn tables:

Line a

Line bTurn table for each node with transfers between

lines who each have been digitised

Line a,b Line a

Line b, c

Line c

c) Network representationby dynamic segmentation and transfer table

Each route is described by dynamic segmentation

(data-base tables maintained by the GIS)

Transfers are described by database tables (not

maintained automatically by the GIS)



• 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)

Background – East Denmark Model (CRM)

The CopenhagenRegion

Funen

Germany

Other areas

Zealand

Sweden

N

EWS

0 20

Jutland

FixedLink

Ferry orboat

40 60 km.



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

Background - CRM

Timetables fromRail and bus co.

Punctuality data

Results

Plan ofoperation

Timetableinterpreter

Frequency-basedtime-tables

Geographic datamodel

Data integrationmodule

Timetablegenerator

Main data model

Bus stops andstations

Road-, metro-and rail links

Zonal map

Supply- andassignment models

Demand models

Reference data

Relational Database Geographical Information System

Data generating module

Traffic forecasting system

Other data



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!



Object oriented approaches (1)

Objects encapsulates:

– Properties

– Functionalities

– Events



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



The Transport Object Platform consists of

• Conceptual model

• Data model

• Programmed functionality in data objects

• Editing and Visualization tools

• Advanced modelling and analysis tools



Data model (1)

L1

L2

Network NetworkLR between features in networks

1 Feature = Sequence of features

+

Infrastructure NetworkRoads, Rail, Tram, Bike,Walk, Intersections, etc.

Basic Public NetworkStops, Terminals, Transfers,Route-building blocks (Route Segments)

Detailed Public Network

Features + Tabular data

Route as sequence of Route Segments

Detailed time-table data in tabular form



Data model (2)TOP Conceptual Overview

RouteSegment

RouteGroup

TimePattern

Route

ROUTES

FrequencyRun

TransportJunction

TransportEdge

Turn

PHYSICALNETWORK

Terminator

Zone

Matrix

Connector

DEMAND

Terminal

Stop

StopGroup Transfer

TERMINALS

DiscreteRun



Data model (3)TOP Conceptual Overview

Terminator

Matrix

Connector

TransportJunction

TransportEdge

Turn

RouteSegment

Terminal

Stop

StopGroupTransfer

RouteGroup

Route

DEMANDTERMINALSROUTESPHYSICAL NETWORK

FrequencyRun

TimeTable

CatchmentArea

To

From

From/to To

To

From/to

From/to

To

At

From/to

From/toSequence of

Sequence of

For Belong to

From/to

Fulfil

Belong to

Belong to

From/to

From/to

DescreteRun

Fulfil



Data model (4)



Data model (5)

TimePatternDiscreteRun

FrequencyRun

«RelationshipClass»RouteDetail

Route

«RelationshipClass»TimePatternDetail

Turn

StopRouteSegment StopJunction

TransportEdgeMatrixMatrixElement

Terminator

«RelationshipClass»RouteSegmentDetail

StopEdge

ESRI Classes::Object

Run

ESRI Classes::Feature ESRI Classes::SimpleEdgeFeature

ESRI Classes::SimpleJunctionFeature

ChangeEdgeConnector

TransportJunction

DEMAND

ROUTENETWORK

PHYSICALNETWORK

Terminals



Stops

TransportEdge

TransportJunction

Stop

StopJunction

StopEdge (default)Linear Reference

Off

set



A Road Network



Stops are added,they automatically connect to the roads



Draw bus routes by clicking nearStopJunctions, where the bus stops and near roads to guide

the bus



The Route automatically swapsto the road network, builds

relationships to the roads and creates Timepatterns



A road is modified…



…and the Route changes.Drivingtime in the TimePatterns is likewise

changed



Grab a Stop and move it…



The Stop triggers move of the StopJunction, which in turn shortens the Route and changes

TimePatterns.



Modifying a road with Stops…



…will modify the Route and TimePatterns and move the StopJunctions, but leave

the Stops



Moving a road and rubberbanding..



…also changes Routes andStopJunctions and TimePatterns



In addition complex schedulingdata like these…



..can be presented in 3D.



Utilising TOP in Public transport assignment models

Different conceptual levels of networks:

• Geographic network

• Organisational network

• Calculation network (logical network, not only a graph)



Multi-modal modelling – extracting the logical network from TOP

Terminator

Transport-Junction

Stop

Stop.Route.Arrival.Run

Stop.Route.Departure.Run

Connector(to Stop)

TransportEdge.Forward

TransportEdge.Backward

AccessEdge.ToStop

AccessEdgeFromTransportJunction

AccessEdge.FromStop

TransportEdge

Stop.Route.Continue.Run

Stop.Route.Enter.Run

Stop.Route.Exit.Run

Route.FromStop.Run

Route.ToStop.Run

STOP

StopGroup

TransportJunction

Connector (to TransportJunction)



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



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

Documents

RULE-BASED OBJECT-ORIENTED MODELLING OF PUBLIC TRANSPORT SYSTEMS