The positive impact of opengis

The positive impact of opengis

Brimmer Sherman
Intergraph software solutions IW17B2 huntsville, Alabama 35894-0001

Abstract
The information technology community is embracing open standards for the obvious cost and performance benefits. Interoperability, componentware, distributed computing, and the Internet are just a few of the driving factors behind this trend. Geodata processing is not far behind. Moreover, the GIS user community will demand that their geoprocessing software exchange heterogeneous geodata and interoperate with other vendors componentware. The current monolithic GIS’S have problems transferring data between heterogeneous and homogeneous platforms and data sources. Geodata model incompatibilities compound this issue. By adopting an OpenGIS standard that defines geoprocessing interoperability specifications, the GIS community at large, will be able to freely access and exchange heterogeneous geodata, interoperate with componentware written by developers from around the world, take advantage of distributed computing and network-based computing, utilize “plug and play” geodata access and geoprocessing tools, and exploit the Internet.

Introduction
The last 10 years have seen incredible advancements in the development of both GIS and the many complementary technologies necessary for the full empowerment of GIS. The development of this emerging science is due in large part to the significant contributions made by many individuals in the academic community, in all levels of government, and in private enterprise.

Whether GIS is used to improve the quality of life or streamline business operations, the benefits of its practical day-to-day application are undeniable. Yet, one thing that will greatly accelerate the use and versatility of GIS technology is geodata interoperability. The software industry’s adoption of componentware and the Open GIS Consortium’s (OGC) OpenGIS specification will provide the framework to enable interoperable geoprocessing.

The use of standard components to build products is a common practice. The manufacturing industry made significant advancements when they incorporated the use of standard parts (componentware) in the production process. This enabled them to take advantage of prebuilt items when building new products. So, to build a new product one did not have to first build the screws and bolts and washers from scratch. Instead, they adapted their designs to utilize the standard components. When this happened the industrial revolution was off and running. Ultimately, we the consumer benefited because goods were now affordable, reliable and productive.

The information technology (IT) industry has lagged behind in the use of componentware. The hardware vendors were the first to use this approach with their manufacturing process and use of integrated circuits. Moreover, they have gone another level further by adopting standard interfaces that allow components to integrate/interoperate together to build a “system”. For example, any brand or size of disk drive will work on a personal computer. Because of the standard disk drive interface definition, there is wide open competition and now you can get a 4GB disk for $400 that ten years ago would have cost more than 100 times that price.

Another major benefit of components and standard interfaces is the ability to take advantage of products that were not available or even invented when the initial product was purchased. For example, if you bought a stereo amplifier in 1975 it would run the turntable and cassette player. Now that same amplifier can run a CD player, which was not available until the early 80’s. The investment in an amplifier was “future proofed”. The consumer was not required to throw out the old amplifier in order to use the new technology. Future proofing is made possible by the use of standard interfaces that define how components will talk to one another.

The software industry is in the process of adopting the component model. The driving force is the market demand for integration, usability, cost and performance. The software industry can only meet these requirements by leveraging and reusing componentware. Object enabling technology, object programming, distributed computing platforms, and open standard interfaces are all enabling the process. The GIS community is following the componentware adoption in the IT industry. And, it will bring GIS into the mainstream of information technology.

Monolithic GIS Architecture
Traditional GIS vendors have had to build and maintain a host of technology enabling Iayers in order to provide their customers with a cost justified geographic solution. The enabling layers include the operating systems, display drivers, proprietary development tools, object models, database access, and user interface tools. This monolithic 165.architecture utilized the accepted IT methodology at the time and produced many highly productive GIS products.

Figure 1. Monolithic GIS Architecture
In a monolithic system, all layers are tightly coupled and not open to other systems, except through the very elemental means of exchanging data with identical monolithic systems or translating data from other systems. This kind of data exchange is referred to as “data transfer.” There are literally hundreds of formats, proprietary and open, and there are hundreds of filters and conversion utilities to perform the format conversions. While this process is workable it is not optimal and needs improvement. As the GE industry moves toward a componentware model, the principal functionality of a GIS can be broken into four basic groups -- the data, the data access, the spatial technologies and end user applications. By componentizing these four parts, each one of the components - like the stereo example, can be supplied by a different vendor - if strict adherence to the “interface standards” are observed. The end result is that a GIS user can now use any customization tools to build an application. They can now choose the most competitive spatial technology. They can use the best data repository technology. And, can access heterogeneous databases. Moreover, these components can now enable integration with the other enterprise IT systems; e.g. office automation, databases, engineering applications, accounting programs, etc.

Figure 2. GIS Components
The data access part of the GIS componentware is defined by the OGC Open Geodata Interoperability Specification (OGIS).

OGC is providing a specification for a software framework for distributed access to geodata and geoprocessing resources. This specification will give software developers around the world a detailed common interface template for writing software that will interoperate with other OpenGIS-compliant software written by other software developers. Most importantly, the specification defines standard interfaces that enables software vendors to produce “Plug and Play” geodata access and geoprocessing tools. Application developers, information managers, and end users -all of whom are part of the global computing revolution -benefit from OGIS compliant software in these ways:

The Application Developer can more easily and more flexibly:

“Write software to access geodata
“Write software to access geoprocessing resources
“Tailor applications to specific user needs, integrating the spatial and non-spatial
“Choose a development environment
Deliver applications on a variety of platforms
“Reuse geoprocessing code

The Information Manager has greater flexibility to:

“Access and/or distribute geodata
“Provide geoprocessing capabilities to clients
“Integrate geographic data and processing into a corporate computing architecture
Choose appropriate platforms -personal computer type, server type, and distributed computing platform type
“Fit the user with the right geoprocessing tools

End users are the ultimate beneficiaries, receiving:

“Real-time access to a universe of geographic information vastly larger than today’s accessible universe of geographic information
“More applications that take advantage of geographic information
“The ability to work with different geodata types and formats within a single application environment and continuous workflow, without being concerned about the details of these types and formats OGIS addresses the basic aspects of the problem of accessing and using geographic data from a variety of diverse sources. A complete and detailed treatment of this topic is provided by OGC in “The OpenGIS Guide”, edited by Kurt Buehler and Lance McKee.

Examples
What does the OpenGIS do for me? A major benefit is the access of heterogeneous data exchange. For example:
A city planner can do an environmental impact study to test the effect of a new pipeline within the central business district. The planner can assimilate population data in one format purchased from a data vendor, gas pipeline data from a utility installation, and satellite imagery in a raster format, allowing inspection of the planned corridor for the pipeline. Using OpenGIS, the city planner brings these different data types together for interpretation in their native format -- without translation. It will foster less data ownership as third party data becomes readily available.
Historically, users of geographic information needed to manage all geographic data for their area of interest whether they owned that data or not. For example, utility companies have spent millions and millions of dollars maintaining land bases. With data becoming more readily available, geographic data users will only “own” and maintain their added value information and not the entire geography. New markets will continue to emerge due to increased awareness and availability of spatial data and applications. Future proof your applications. As with the stereo amplifier that could use a CD player. Today’s applications will be able to plug in new data repository technology as it becomes available, without having to be rewritten.

Conclusion
GIS technology is being incorporated into mainstream information technology as the use of componentware is adopted. The definition of OpenGIS is a major enabling factor in this process. The OGIS specification provides a framework for software developers to create software that enables their users to access and process geographic data from a variety of sources across a generic computing interface within an open information technology foundation. The end users ultimately benefit by being able to painlessly select the best software to meet their production requirements.