ArcGIS Network Analyst

ArcGIS Network Analyst and the Network Dataset Patrick Demer  ESRI - Boston

Agenda • Network Analyst • Network Dataset • Demos

ArcGIS Network Analyst • Everything in ArcView GIS 3x and more – Routing – Directions – Network Analysis

• Tight Integration with Geoprocessing – Models and Scripting – ArcToolbox tools

• New Network Dataset – Core Geodatabase enhancement

ArcGIS Network Analyst • Network Analyst object model – Extensible, support for custom applications

• Migration path for existing software – Workstation Arc/Info Network – NetEngine – ArcLogistics Route – ArcIMS RouteServer 

• Framework for future development – New solvers – New Network Dataset enhancements

ArcGIS Network Analyst Integration and Migration Arc Workstation Arc Network module

ArcEngine ArcGIS Server 

ArcView GIS 3.x Network Analyst extension

ArcGIS 9.1 NetEngine ArcLogistics ArcIMS

Network Analyst Extension

Continued Network Analysis Functionality

ArcGIS Network Analyst (Desktop) • ArcMap – Interactive toolbar and dialogs

• ArcCatalog – Dialogs and wizards

• Geoprocessing – Modeling and scripting – Toolbox

• Network Dataset – Supports Shapefiles, PGDB, SDE, and SDC

• Network Analyst Solvers – Pathfinding and allocation algorithms – Extensible via ArcObjects

Network Extension (Server and Engine) • ArcGIS Server  – Network Extension – Centralized computing solution – Internet and Intranet support – Enterprise computing environment – Scaleable and IT compliant

• ArcGIS Engine – Network Extension – Embeddable components – Lightweight applications

Network Analyst Solvers • Routing – Multi-point routing (time windows supported on stops)

• Closest Facility – Fixed and mobile asset routing – Emergency response

• Driving Directions – Expandable inset maps – Auto generation capability

• Service Areas – Complex polygon generation – Allocation across networks

• OD Cost Matrix – Origin and destination calculations, spatial interaction – Custom algorithm support

Goal: Model Real World Networks

multi-modal network support

Goal: Model Real World Networks Streets

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Subway Light Rail B

multi-modal network support

Network Dataset

Network Dataset • New network model • Enhanced modeling capabilities – turns / maneuvers, multi-modal networks – advanced attribute (weight) model

• Borrows concepts from topology – dirty areas and incremental build

• Works with Network Analyst extension

Network Dataset • Built from simple features – no special features like Geometric Network

• Features participation: – may also participate in a topology – may participate in either a network dataset or geometric network

Network Dataset • Supports Shapefiles – Direct use of shapefiles

• Supports Personal Geodatabase – Desktop users

• Supports Enterprise Geodatabase – Large Networks – Multi-user server environments – Scalable

• Supports direct reading of SDC

Network Sources • Line features – define one or more edge elements

• Point features – define junction elements – Required for multi-modal network

• Turn features – define turn elements in network – explicitly models subset of possible transitions between edge elements during navigation – unspecified transitions assigned default turn attribute value – From-To Node tables are not supported

Turn Features • Turns are features – Simple line feature class – Model a turn as a sequence of  any number of connected lines

• Turns do not alter  connectivity, but traversability – e.g., U-turn restriction

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Turn Features • Simple two-part turns • N-part turns • Restrictions – based on vehicle characteristics – legal restrictions

• Default turn penalties – part of the network attribute model • “All U-turns are restricted” • “All left turns cost 30 seconds”

Connectivity Model • Controls how features are connected • Simple rules-based approach • User defines connectivity model – used when the network is built and the connectivity is updated

• Connectivity is consumed by tools implementing analysis algorithms

Connectivity Model • Supports definition of multi-modal networks – ocean freighter, rail, and road network – road, highway, subway, and bus network – water, sewer, and stormwater network

• Two typical usage patterns – endpoint elevation – simplest (ArcView 3.X) – midspan / multi-modal – extending the GN model with connectivity groups

Endpoint Elevation • Easiest to use – algorithmically simple for analysis – used in ArcView 3.x Network Analyst

• Connectivity only at endpoints • Think of elevation as a logical connectivity group rather than a true z elevation

Midspan / Multi-modal • Endpoint and mid-span connectivity supported – complex edge feature model

• Line classes assigned to a single group – any number of groups permissible – connectivity only within a group

• Point classes assigned to any number  of groups – can be used to fuse groups together 

Point Feature Connectivity • Point classes may span multiple connectivity groups – used to create connectivity between lines in different groups Connectivity Group 2 Connectivity Group 1

Attributes • Control navigation through the network • May be used to accumulate information • Associated with network elements – “similar” to weights in a geometric network

• All elements have the same set of attributes • Edge elements are directed – attributes defined for the edge in either direction

Attribute Types • Cost – accumulated as you traverse a network element (e.g., distance, travel time) • Descriptor – true for the entire length of the element (e.g., material type) • Restriction –like a boolean condition (e.g., no travel on one-way roads) • Hierarchy – three level classification of edge elements; e.g., 1 = highway 2 = major road 3 = surface street

Evaluators • Return the value of an attribute for a network element • Three provided: – Constant – Field – VBScript

• Custom evaluators can be written by third parties

Network Dataset vs. Geometric Network Network Dataset

Geometric Network

transportation modeling

utilities/natural resources modeling

pathfinding & allocation operations

network tracing functionality

turns supported

turns not supported

uses simple features: points and lines

uses custom features: simple/complex edge features and junctions

more robust attribute (weight) model

weights based on feature attributes

user controls when connectivity is built

system managed connectivity

Network Dataset Summary • Motivated by transportation industry • Contain edges, junctions, and turns • Connectivity re-established at usercontrolled times • Multi-modal connectivity models • Richer attribute model • Features may participate in a topology • Shapefile support • Requires network analyst extension

ON TO THE DEMOS