Implementing Geometric Networks in PODS ESRI Spatial 5.0

1. ImplementingGeometric Networks in PODS ESRI Spatial 5.0 J. Tracy Thorleifson Eagle Information Mapping, Inc.

2. Contents Linear Referencing in Geometric Networks & Arc Schematics 1 Overlapping edges in Geometric Networks 2 Options for Network implementation in PODS ESRI Spatial 3 4 Example implementations

3. Linear Referencing in Geometric Networks • Do edge features in a Geometric Network support measures? • Yes! • Edge features support both measure and Z values • Can edge features in a Geometric Network be used as route features for route event layers? • Yes! • Any Polyline M edge feature class in a Geometric Network can be used to support route event layers

4. Linear Referencing in Arc Schematics • Do links in an Arc Schematics feature class support linear referencing? • Yes and no… • M values from the data source feature class are not preserved • Link features in a Schematics feature class store M values, but these values are set by Arc Schematics • Identify M’s tool does not work with a Schematics feature class • Can Arc Schematics link features be used as route features for route event layers? • No, but… • Arc Schematics supports “Node on Link” and “Sub Link” feature types • Custom XML Builder and/or geoprocessing code is currently required

5. Topology in a Geometric Network • Network topology is determined solely by spatial coincidence of junctions and edge-ends • Overlapping edges do not result in connectivity or geometry errors as long as junction / edge-end topology is maintained • Editing considerations • Any editing tool that maintains junction / edge-end topology is necessary and sufficient • Generic ArcMap Edit tools – make sure to properly manage the ‘snapping’ environment • Junction edits in a geometric network also move connected edges; edges are ‘anchored’ at the next junction • Can be problematic in PODS ESRI Spatial where all online features may not participate in the network – non-network online features will not move • Centerline edits should be ‘anchored’ by control points – the net junction adjacent to the one being edited may not be a control point, causing the introduction of a centerline deflection without a corresponding control point

6. Overlapping Edges in Geometric Networks • Overlapping edges of different types for a single entity (e.g. a single pipeline) are not a problem • There is only a single path through the overlapping edges • Find connected, find path and trace all work • Find loops is useless, since all overlapping edges are ‘looped’ by defintion • Overlapping edges for two or more entities (i.e. multiple pipelines) are a problem • The network analysis tools can’t tell that the overlapping edges belong to different entities • Find connected, find path, find loops and trace return spurious results

7. Considerations for implementation • Primary intended use • Support for hydraulic modeling? • Outage modeling? • Creation of schematic diagrams? • Geometric networks require feature classes as input • Route event-based layers cannot be used in a geometric network • In implementations with overlapping edges, use the complex edge type for edge features

8. Geometric Network Option 1 – “Classic” • Only include features in the network through which product actually flows • Pipe segments, valves, tees, meters, taps, etc. • Model sources and sinks • Model connectivity rules • Best for: • Supporting export to hydraulic modeling applications • Application of network analysis tools in ArcMap • Outage modeling, flow tracing, etc.

9. Geometric Network Option 2 – “Schematic” • Include all features in the network that you might want to see in a schematic diagram • StationSeries + whatever! • Don’t worry about sources and sinks, or connectivity rules • Best for: • Arc Schematics diagram creation • The standard builder is optimized for geometric networks and deals nicely with all feature classes participating in the network

10. Geometric Network Option 3 – “Event-Based” • Include only StationSeries in the network • Use schematic diagram rules to add non-network features to a schematic • Spatial query rule • Relationship rule • Use a custom XML builder to include route events in a schematic • Best for: • Really only useful for schematics generation, as non-network features appear only in the schematic diagram

11. Sample Steam Injection Network

12. Steam Injection Legend

13. Option 1 – Schematic for “Classic” Network • All product-carrying features participate in the network • PipeSegment is the only edge class • StationSeries is not included

14. Option 2 – Schematic for “Schematic” Network • All product-carrying features participate in the network • PipeSegment and StationSeries are both present as complex edge features

15. Option 3 – Schematic for “Event-Based” Network • StationSeries is the only feature class in the network • Cogen, Well, Well Tester, Steam Manifold and Closure are all “offline” features • Placed in the diagram with a spatial query rule

16. Conclusion • Geometric networks are wholly compatible with linear referencing as implemented in PODS ESRI Spatial • Overlapping edges resulting from StationSeries features and online polyline event features are generally a non-issue • A variety of options are possible when implementing a geometric network with PODS ESRI Spatial • The option selected is dependent on intended use of the network • Arc Schematics paired with a geometric network-enabled PODS ESRI Spatial Geodatabase is a useful display and visualization tool