The metamorphosis of GIS – Is AM/FM dead?

Historical Perspective

When Hardware Was King
It was January 1982. The third largest independent Telephone Company in the U.S had just hired me as their corporate manager of outside plant. One of my first assignments was to cochair a project to automate our department’s engineering and plant records. Only later did we learn that the industry called this an Automated Mapping/Facilities Management (AM/FM) System.

Even though this effort was relatively early in the evolution of AM/FM systems, we knew that other telephone and utility companies had had similar systems in place for several years. The difference was that we wanted our system to not only automate the drafting and records-keeping processes, but also eliminate the separate drafting step by allowing the engineers to design directly on the system, yielding a work order as a result. So, as far as we knew, this was the first time that direct engineering design and work order generation was a functional requirement of an AM/FM system. Aside from design, our system would also have to perform productivity functions such as rippling of cable count changes and providing loop-make-up reports. Obviously these requirements dictated that the system use a connected-network topology.

As we investigated the systems available, we discovered that there was a separate class of computer graphics system that also operated using a geographic base map. These provided various analytical functions relating to land areas or the coverage of environmental resources. These systems were built using a polygon-based topological data structure rather than the connected-network model of AM/FM systems. They were called Geographic Information Systems (GIS) or when used for parcel mapping by local governments, Land Information Systems (LIS).

A common thread between these two types of systems was that the hardware component was a major consideration of system design. Systems were implemented using a mainframe or minicomputer that were directly connected to dedicated graphic display terminals, either manufactured by a third party or manufactured by the AM/FM vendor. In those early days, it was not untypical to spend the better part of a $Million on the CPU and supporting hardware such as external hard and tape drives, memory and specialized boards that communicated with the graphics display terminals.

Color – At A Price
The very first demos that our evaluation team saw were based on vector-based, storage tube graphic display terminals. These were typically monochrome (usually amber or green) and displayed the image by a stream of electrons that would “trace” the vectors (including text fonts) of the map on the screen. The problem with this type of display was that as the complexity of the map increased, the resulting image would dim. Thus there was a practical limit to the density of the data being displayed. Fonts had to be extremely simple or they would significantly degrade the image.

At this same time, a couple of the major AM/FM vendors had relatively new or just announced raster display terminals. This type of display used a CRT (cathode ray tube – as is used in today’s monitors) instead of a storage tube and was not susceptible to dimming because of data density. It presented its own problems, though. The vectors contained on the map had to be “rasterized”. Thus an additional processor was required in the display terminal. A high-speed communications link was also required to connect to the main computer or CPU (central processing unit). Typically the connection hardware and protocol used in this connection was proprietary to the vendor, as there were no standards for such at this time. As these displays replaced storage tubes, a typical configuration used two 19” displays on top of an integrated digitizing table. The manufacturers called them graphics workstations. We affectionately called them two-headed monsters.

As we planned our hardware expenditures, we determined that a maximum of eight of these workstations could be connected to the CPU. Even then, response could be slowed significantly in this configuration. A dual monochrome 19” graphics workstation went for around $60K. If you wanted color, you had to add at least $10K for each color CRT used instead of the standard monochrome.

Proprietary Graphics and Flat File Databases
As far as the software was concerned, both GIS and AM/FM systems linked non-graphical information or attributes to graphical entities. The graphical engine employed in these early systems was unique to the particular vendor and the graphics were stored in proprietary formats, separate from the non-graphic or attribute data. The non-graphical information typically was stored in either flat files or hierarchical databases.

Geographic Information Systems differed from AM/FM systems in that they dealt with the underlying geography directly, rather than as simply a means to display facilities. That is, they dealt with polygons as well as line and point features, and could easily handle more complex spatial relationships of those features. They used a topological data model whose graphic primitives included points, arcs and polygons. Therefore these systems modeled the relationship of geographic features to one another well thus being able to, for example, display point symbols within an area, or determine the closest distance between features.

Later, telephone companies and utilities that had implemented AM/FM systems found that their use was limited to analysis and management of facilities and they could not easily perform spatial analysis. Many found that they had to implement both systems – AM/FM in their planning or engineering department and GIS in their marketing or customer service department. A system that could perform both facilities and spatial analysis was needed.

(Geo-) Relational and Standard Hardware
By the 1990’s, AM/FM software vendors began striving to add GIS functions comprising basic polygon processing to their systems. Conversely, in this same time frame GIS software vendors began adding network tracing and analysis capabilities. Part of this move came from the ability to relate entries in the non-graphic database to their position (XY coordinates). This was handled in either an external way, which was called a geo-relational database, or internally where XY coordinates were stored directly in a relational database.

The Blurring of AM/FM and GIS
It was the increased use of commercial relational databases in both GIS and AM/FM systems, which allowed similar functions to placed into both types of systems. This overlap of functionality led to the blurring of the differences between AM/FM and GIS. In fact, the industry began to call all systems that handled facility management and spatial analysis AM/FM/GIS (or even just GIS), regardless of their underlying data model.

Today, each of the top-selling AM/FM/GIS software systems still has one of the two underlying data models at its core. The AM/FM-based system, which, because of its network model, tends to be implemented only on a departmental basis. The GIS-based system, which, because of its topological data model, tends to be more interdepartmental or usable throughout the enterprise. The capabilities (or limitations) of these two models will become more prevalent as utilities demand more efficient access to spatial corporate data from all departments.