The maps and apps that comprise ArcGIS for Water Utilities are built around the Local Government Information Model, so we thought it would beneficial to explain what the Local Government Information Model is in this blog and in a follow up blog explore its benefits for water, wastewater and stormwater utilities.
We’ll start by breaking down the term Local Government Information Model into two parts “Local Government” and “Information Model”.
ArcGIS for Water Utilities is a module of ArcGIS for Local Government. ArcGIS for Local Government is organized around typical services or functions of a local government – water, sewer and stormwater utilities, public safety, land records, public works, etc. From a GIS perspective, no matter what type of entity a water utility is – a municipal department, an authority, part of a county, part of national government, private or a public private partnership, the scale of the data necessary to effectively map and manage your utility is similar to the scale of GIS data used by other local government entities. Simply put, water utilities need local scale GIS data.
The feature classes and feature datasets in the Local Government Information Model are “harmonized” meaning that they are designed to work across and support typical functions of local governments without duplication and redundancies. This enables municipal departments, functions within an organization or entire organizations to manage data that is specific to their domain and utilize data from other domains within local government as base data.
If you look across a typical city enterprise GIS implementation that encompasses all of a city’s departments, what you’ll notice is that the “operational data” of one department is often “base data” for another. For example the parcels maintained by a city’s land records department are typically base data for the city’s water utility. The water utility may use the attributes of the parcels for analysis or may join a table to the parcels with water utility specific information. Another example is the GIS features of a city’s storm water system that are maintained by the water department but are used as base data for the city’s 411 system that is managed by the city’s public works department. It’s important to point out that when we say “base data” we don’t just mean the data is used as a base mapping layer, it can be used for analysis or can be extended by the utility (in the example of joining a table of utility created data to a parcel data). Data not maintained by the utility is used as base data to provide perspective but can also blur the lines and become operational data when used for analysis or joined to information maintained by the utility
The same logic applies to water utilities that are authorities or private companies. Some of the layers they use for base data typically come from other local units of government (cities, towns, counties) within their service territory.
We are using the term Information Model because this is more than just a data schema. In the GIS realm the term “data model” has commonly implied a schema or database structure only. The Local Government Information does include a schema, but we consider things like the Map Documents for our maps and apps and specifications for services to be part of the information model as well.
We are including Map Documents in the Local Government Information Model for two main reasons. First the Map Documents for our maps and apps are built upon best practices for each particular type of map. For example in the Mobile Map Template the .MXD documents have been designed to show best practices for building an interactive water utilities map for field crew use.
Secondly the maps and apps are built specifically for the geodatabase schema that is part of the Local Government Information Model. What this means is if you change the underlying schema to better reflect the true organizational needs of your utility than depending on the changes made you may have to modify any map documents that use that layer. Since you use the Map Documents to publish services to ArcGIS Server than the same logic applies for including services in the Information Model. The schema, the map documents and the services are intertwined.