Network Analysis

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Network Analysis
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Overview

• GIS deals with the interrelated nature of
  geographic data
• Some data has specialized rules, parameters and
  restrictions on interaction
• Measurements, relationship-testing and analysis
  must all occur within this framework

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Overview

• Network analysis focuses on edge-node topology to
  represent real-life networks of information
• Driving Directions
• Multi-modal routing
• Information networks
• Electricity, water, sewer, natural gas

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Edges and Nodes

• Series of nodes connected by edges
• Each edge starts or ends at a node
• Each node touches at least one edge
• Planar or non-planar networks
• Bridges, tunnels, etc
• GIS needs to know what data is part of the
  network and what is simply just data

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Network Properties

• In order for our network to function, we need the
  following
• Base data (our edges and nodes)
• Cost to traverse the network (dist, time, other)
• Restrictions on travel (one way, no left turns)
• Temporal information at a given time
• Is there a higher cost to traveling the network?
• Are there additional restrictions on our use?

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Network Participation

• In ArcGIS, feature classes that participate in a
  network must all reside within a feature dataset
• Feature datasets are only in geodatabases
• The GDB stores additional information about the
  network and its parts
• Types of network edges, connectivity rules,
  impedance, etc

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Network Attributes

• Cost
• Length of edges
• Time to travel along edges
• Financial cost to traverse network
• Restrictions
• One-way Streets, No Left Turn, etc
• Height/weight (vehicle class) restrictions
• Temporal Restrictions (school zones, flooding)

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Network Uses

• Once our network is complete, we can perform
  analysis on our network
• Shortest Cost Path
• Network Flow
• Service Areas
• Routing

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Network Interface in ArcGIS

• Network Analyst is an extension to the ArcGIS
  Core
• Extensions must be enabled to use
• Enabled in both ArcMap and ArcCatalog

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Network Analysis Toolbar
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Network Analysis Panel

• Creating a new Route, Service Area, etc. from the
  Network Analysis menu will add it to the Table of
  Contents
• The Network Analysis panel provides you
  additional access to network-derived data