Open GIS interfaces: The glue for geospatial interoperability
Where this methodology is helpful
While theoretically the ideas of OpenGIS sound plausible, implementation of the
interfaces in products, and use of those products, can only occur if there are good
supporting business reasons. So, it is fair to ask how will products that support these
interfaces add value for businesses in the utility sector.
Utilities should be drawn to open standards for a few reasons. First, open published
standards will not lock them into a proprietary system and the vendor who created it.
Organizations are free to work with a variety of vendors and integrators who need access
to the specification, not proprietary code. Second, utilities are growing more and more
by acquisition. And, as a result, new GIS systems are being added to the organization.
There are always two options for managing mixed environments: keep a heterogeneous
environment or convert to a single system corporate-wide. Each has its costs. However,
being able to keep both running while "connecting the two" via open interfaces cuts
down on purchases as well as training.
Interoperability at the interface level provides a means to replace a component of a
system that becomes outmoded, or more likely, enhanced significantly by the same, or a
new vendor. There is ample opportunity to switch out just that component for a new one
that exposes the interface.
Finally, organizations that participate in the creation, and hopefully, implementation of
the interface specifications are truly on the cutting edge of technology. They have shown
their willingness to strive for consensus and work with other organizations, likely their
competitors. That experience can only reflect well on their ability to reach consensus
within large organizations, such as utilities, and serve as resourceful integration partners.
Examples of interoperability
Interfaces and Implementations
While the OGC does have several specifications published, only a handful of vendors
have implemented them. Those organizations tended to be very involved in the
specification development. Further, many of the initial specifications were
"groundwork" specifications defining the most basic elements needed for future
interoperability: simple features, grid (image) coverages, catalog (metadata),
transformations (projections). These in and of themselves certainly can be implemented,
and have been in a handful of products, but perhaps their real role was to underlie what
was to come: interoperability on the Internet.
Web Mapping Test Bed I
The first fast track interoperability initiative, begun last year, revolved around developing
interoperable interfaces for Internet map servers. The idea, in short, was to find a way to
capture information from many different "brands" of web servers using a standard
interface and bring them together for an answer to a question. The end user simply sees
the answer (often a map) and need not know the underlying mechanics - such as
searching for the correct data, putting it in the correct projection - etc. The resulting
specification was made public in April 2000.
Later that month Cubewerx of Canada shipped the first product compliant with the
specification. And, NASA, in September, one of the sponsors of the Test Bed, purchased
the Cubewerx Map Server. Other implementations are in the works from other
participants with little or no fanfare. Since some of the organizations showing the most
interest are the data holders, such as NASA, future use of their data may depend on being
interoperable.
What's Next?
The vision is that more and more software vendors will offer compliant servers to make
Web mapping interoperability a reality. But that can only come with customer demand -
if users do not place a high value on interoperable systems, vendors will not build them.
And, if only one system exposes the interface, very limited connections are possible.
OGC works in tight conjunction with ISO, and many initiatives are being fast tracked
there. Since more and more governments and others, turn to ISO as a guide for software
selections, they may soon be turning to OGC specifications. And, in parallel, many of
the new developments in GIS and GIS research are building off of the public
specifications as a starting point, underlying much of what lies ahead.
Utilities, like telecommunications companies, see interoperability as both a blessing and a
curse. The vision of easier sharing of resources is appealing, but the energy to get there
may seem significant. As more utilities take further advantage of the Web, both
internally and for customer services, conformance with interface standards can only
grow.
