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Geometric Network

Robert Borchert

GIS Technician

United Services Group

Great River Energy

Geometric Network: What is it andhow to make it?

This paper will explore an important element ofArcGIS for electric utilities, the Geometric Network.Included in this discussion will be why you would want aGeometric Network, examples of how you could use aGeometric Network utilizing the Utility Network Analyst,and a step by step method for creating a GeometricNetwork. All content presented here pertains to “Out ofthe Box” ArcGIS. Also we will attempt to address someof problems you may encounter while creating yourGeometric Network and steps you can take beforestarting that may help your effort.

Geometric Network

• What is a Geometric Network?

• Why you may want a Geometric Network?

• Why may you not want a GeometricNetwork?

Geometric Network

• Examples of how you can use aGeometric Network.

• What is required to create a GeometricNetwork?

• Basic procedure to create a GeometricNetwork.

Geometric Network

• Some of the problems you may encounterwhen creating or using your GeometricNetwork.

• Steps you can take before starting

What is a Geometric Network?

• Single dimension non-planar graph withfeatures

• Edge elements and junction elementsconnected by topology

Or more simply…

• The GIS knows how things are connectedfrom point “A” to point “B”

• Direction of flow– Source to end

• Dot to Dot puzzle

Connecting the Dots

• Collection ofnumbered Dots

• Connected by lines

Connecting the Dots

• What are the Dotsand Lines?– Substations

– Reclosers

– Fuses

– Transformers

– Poles and Risers

– Customers

– Underground orOverhead Conductor

What is a Geometric Network

• Direction of Flow– Path of travel

– From substation tocustomer

– Multiple branches

– Independent ofpolyline direction

Why you may want aGeometric Network?

• Generate Reports– Find “B” phase transformers and

total Kv on north feeder

– Select Create Report or CrystalReport Wizard

• Outage management tool

• Drawing errors– Unconnected drawing elements

– Loops

• More efficient editing– Keeps elements connected

Why you may not want aGeometric Network

• Less efficient editing

• Only one network element per location

• Cannot load new data

• Labor intensive

Examples of how you can use aGeometric Network

• Utility Network Analyst– Tracing

• Downstream

• Upstream

– Outage management tool

– Find Loops

– Mass selection and Update

Utility Network Analyst Toolbar

Flags and Barriers

Trace TaskSolve Button

Tracing

• Downstream Trace– Add Flag

– Perform Trace(SOLVE button)

• Upstream Trace– Place the Flag

– Perform Trace(SOLVE button)

– Traces a direct path

Outage Management Tool

• Customer calls– Place Flag

– Perform TraceUpstream

• Highlights possibleproblem spots– Transformer

– Fuse

– Recloser

Outage Management Tool

• Second Customercalls

• Place second flag onthat customer

• Find CommonAncestors

• Highlights commoncomponents

• Third Customer calls• Fourth Customer calls

Find Loops

• Drawing error

• Circuit crosses backto itself

• i.e. short circuit

• Missing element– Switch

– Open

– Etc…

• Crossing Lines

Find Loops

• Place Flag atSubstation or on theconductor

• Find Loops– Perform Trace

• Make Corrections

• Proper flowestablished

Mass Selection and Update

• Set SelectableLayers…– Customers

• Place Flag• Perform Trace

Downstream• Update based on

Selection– Attributes Window– Calculate Values

What is required to create aGeometric Network?

• ArcEditor or ArcInfo

• ArcCatalog

• Geodatabase

• Same Feature Dataset– Standard Data Model

• Note on ArcView and ArcReader– Cannot edit network elements

– Will not publish for ArcReader

Basic procedure to create aGeometric Network

• Make a backup

• Can corrupt your drawing

Basic procedure to create aGeometric Network

• Start ArcCatalog• Right Click the Feature Dataset• Select

� New� Geometric Network…

Build Geometric Network Wizard

• Step by step wizard…

Build Geometric Network Wizard

• Build a geometric network from existing features

Build Geometric Network Wizard

• Select the features classes and name for your Geometric Network

Build Geometric Network Wizard

• Enabled values

Build Geometric Network Wizard

• Complex or Simple edges

Build Geometric Network Wizard

• Snapping

Build Geometric Network Wizard

• Sources and Sinks

Build Geometric Network Wizard

• Weights

Build Geometric Network Wizard

• Summary

Build Geometric Network Wizard

• Building the Geometric Network

Build Geometric Network Wizard

• Same Feature Set as Network Elements

Problems

• Only one Feature Class per location– That is the same X,Y value– By design

• Loops– Missing drawing items– Incorrectly placed polylines

• Many features may not be connected– Automatic snapping in the Build Geometric

Network Wizard

Automatic snapping in the BuildGeometric Network Wizard

CAUTIONBefore SnappingAfter Snapping

Problems

• Cannot produce flow fromthe substation or source

• Check the AncillaryRoleand Enabled fields

• AncillaryRole – substations arethe source

0 - None1 - Source2 - Sink

• Enabled – a component isactive or inactive in the network

0 - False1 - True

Steps you can take before starting

• Point features areconnected– Select By Location

– Do not use Buffer

– Mark those points

• Connect Points

Steps you can take before starting

• Determine position of switches and statusof areas where there can be an open– Update a column with that status

• 0 = False = Open

• 1 = True = Closed

– Can then update the Enabled field aftercreating your network

– If you delete your Geometric Network theEnabled field remains intact

Set Flow Direction

Flags and Barriers

Trace TaskSolve Button

• Start an edit session

• Generate Flow Button

Generate Flow

Set Flow Direction

• Display Arrows Button• Set Flow Button

Questions?

Acknowledgments

• I would like to thank the GIS Team atUnited Services Group for their input forthe content of this presentation.

End Notes

• This paper was developed from personalexperiences and is not intended as amanual or the “right” way to perform theoperations covered.

• This paper is also only intended as a basicintroduction to Geometric Networks for themore advanced users.

References

• All specific material in this paper wasderived from the experiences of the GISTeam at United Services Group or wasparaphrased from the help section ofESRI ArcGIS 8.3

Author Information

• Robert D. BorchertGIS Technician

United Services Group

w/ Great River Energy

17845 East Highway 10

Elk River, MN 55330-0341

Phone (763) 241-2211

Fax (763) 241-3715

rborchert@usgweb.com

www.usgweb.com

www.usgweb.net