Introduction to Network Analyst(adapted from ESRI Lessons)

GEOG 4650/5650

2009 Spring

Week 2

Goal : to model real-world networks• Solving

transportation problme

• Road – interstates,

• Streets

• Railroad

• Busline

• Turns

What does it solve?

• Best route – find best route

• Closet facility – find closet pizza store

• Service area – find streets/zone from distance

• Origin-destination cost matrix

Network Analyst in ArcMap

Toolbar

Designing the Network Dataset

• Network dataset can be shapefile,geodatabase or SDC dataset

• Shapefile supports one edge source• Geodatabase supports multiple edge and

junction sources• SDC – highly compressed countrywide street

network (purchased from vendor)• Build Network Dataset : From ArcCatalog or

ArcToolBox | Network Analyst | Network Dataset | Build Network

Attributes of street files• distance, travel time, etc. For best results, name these fields the units

of your impedances, as these fields will automatically be detected by the New Network Dataset wizard -- for example, you may want to name your travel time field "Minutes". For edge sources, if the impedance values differ based on direction of travel, provide a separate field for each direction of travel -- for example, "FT_Minutes" and "TF_Minutes".

• If you are modeling one-way streets, be sure that your edge sources have a field specifying one-way street information. The New Network Dataset wizard will recognize a string field named "One_Way" or "Oneway", creating evaluators that interpret its values as follows: – "FT" or "F" indicates a one-way street only permitting travel in the digitized

direction of the edge. – "TF" or "T" indicates a one-way street only permitting travel against the

digitized direction of the edge. – "N" indicates a street that does not permit travel in either direction. – Any other value indicates a street that permits travel in either direction.

Traveling Salesman Problem…..

Barrier

Creating Network Dataset

• Start ArcCatalog

• Right-click Street layer

• Select New Network Dataset