ArcGIS Facility Utility Network: Associations
June 30, 2017
by Robert Krisher
Senior Consultant at POWER Engineers
This article was originally published as a LinkedIn Article
In my continuing quest to introduce ArcGIS users to the new terms and concepts being introduced by Esri’s Network Management platform, this article will help demystify the new ability of modelling Associations within your Utility Network. The first question to answer is ‘what are associations’? The answer to this is simple; associations are the way that the new Network Management model represents the various relationships between elements within the Utility Network. The first and most familiar form of association that the new utility network models is connectivity, however Esri has made several enhancements to the way it can model connectivity.
Connectivity is the foundation of all of the tracing and analytical capabilities of the Network Management platform; it defines what and how all of your equipment is connected. However the new Utility Network actually supports three different types of connectivity.
Simple Graphical Connectivity
The first form of connectivity is the one that is most familiar with users of Esri’s old Geometric Network and is based off of spatial coincidence. Whenever a point and a line feature are coincident with each other the utility network model will check its connectivity rules to see if they are allowed to be connected, and if they are it will automatically establish a connectivity association between the two features. This is referred to as simple graphical connectivity because you can look at the map and immediately tell exactly how the objects are connected up to each other.
Complex Graphical Connectivity
In contrast to simple graphical connectivity, complex graphical connectivity makes use of a new functionality called terminals in order to establish the association between features. In the Utility Network data model every asset group or asset type can have a series of terminals that provide different attachment points on the feature along with different paths of connectivity within the asset. In the case of a transformer, we would define terminals for the high side and low side of the transformer and specify that this is a directional connection, that is to say that power can only flow from the high side to the low side. In the case of a switch we would define two named terminals and specify that this connectivity between these terminals is bi-directional.
Because terminals are used to establish the default connectivity between features it’s worthwhile to review connectivity rules to make sure that they are as specific as possible so that features are automatically connected when they are created. There are a few situations where default connectivity for a newly created feature cannot be determined, but if this happens you can simply manually define the association between the two features. This ability to manually establish connectivity between two features actually leads us neatly into the final form of connectivity associations, logical connectivity.
While the combination of connectivity rules and terminals allow for a more precise network model, the feature that takes the utility network to the next level is its ability to model logical connectivity between features that aren’t graphically coincident. For customers who are planning on modelling device internals this functionality is the key to establishing the internal connections between the different devices and their connection points. With the device internals all modeled, the next step is for us to define an assembly to relate all of the pieces to a common feature and fortunately the network management tools have one final form of association that does just this.
The concept of containment is fairly straightforward, it allows one feature to be defined as the parent or container for a number of smaller features. While it is possible to model parent / child relationships in the current generation, containment in the new model takes the concept to the next level by extending the concept to any assembly or banked feature in the GIS while also providing several tangible benefits to the user experience as well as the map products produced by the application.
The main benefit of establishing a containment relationship is that, if desired, you can have the components within an assembly automatically turn off until a user explicitly views the internals of the container.
The next benefit is that when performing traces and generating diagrams you have the option to either include the assembly with or without its contents in your analysis. In the case of tracing, this feature is a nice way of cutting down on the number of features in your results for some of your reports and analysis. Where this feature shines is in the generation of diagrams, as it not only greatly reduces the number of features you have to lay out in your schematic but it also reduces the number of feature that need to be synchronized in the layout.
The final type of association in the new network is the ability to establish attachments between structures and network features. While the main reasons for using this new method of attachment instead of a relationship is quite technical in nature, there are some very practical benefits to it. Firstly, it provides a common model and framework for handling the relationships between equipment and locations in your GIS. I liken this to the common Asset / Location paradigm used by most major asset management tools. The second benefit of this approach, and of the entire model, is that it provides a consistent model and platform that increase the ease with which the GIS may be integrated with external systems for use with Asset Management, Engineering Analysis, etc. A third benefit is that because this provides a consistent way of modelling the relationships between networked and non-networked items, the network management tools now have built in options similar to containers that allow either including or excluding associated structures in tracing networks and creating diagrams.
At this point in the series we’ve covered all of the small pieces of how the new network model works. We now understand how to model all of our assets and the relationships between those assets. We also understand how the different associations between our objects can be used to affect our tracing and analysis. In my next article I will take a step back and show you how the new network model allows you to accurately model different styles of networks that the previous geometric networks couldn’t handle.
About the Author:
Robert is a Senior Consultant in POWER’s Geospatial and Asset Management group with over 10 years of industry experience. Robert excels at pushing the boundaries of what is possible with GIS and related technologies at utilities, often by repurposing proven technologies and methods in clever ways. As an active member of many early access programs across the industry and author of more than a dozen published articles, Robert is a recognized expert with Esri’s latest technology including ArcGIS Pro and the new Utility Network. He loves finding innovative solutions to complex challenges and sharing his insights with the GIS community. If you have any questions or comments for Robert, you can contact him at firstname.lastname@example.org.