Making the pieces fit
- By Cheryl Gerber
- Sep 19, 1999
As geographic information systems have moved into the hands of general users, the software has grown more interoperable and easier to use. However, significant interoperability hurdles still prevent the GIS market from realizing its full potential.
Although standards and the increasing use of the Internet have overcome some of those problems, the GIS community is tackling the larger problems of enterprise geospatial data management, incompatible data structures and disparate interfaces.
"Interoperability is still the biggest problem that prevents the acceptance of GIS in the mainstream," said David Sonnen, senior consultant for spatial information management at International Data Corp. But the highly specialized GIS vendor community, which used to operate in a kind of skunkworks environment, has made progress. "They slowly came around to where they would allow their data to be exchanged, but it's still a problem," Sonnen said.
When GIS began to enter the mainstream three years ago, vendors had to adapt. Since then, the market has continued to expand.
"We're going to see a tremendous growth in the use and value of geospatial information. The number of geospatial information users is going to explode," said Fred Limp, director of the Center for Advanced Spatial Technologies at the University of Arkansas. Limp is building a warehouse of Arkansas geodata. Limp and Sonnen point to progress made by the 184 members of the Open GIS Consortium Inc. (OGC) as evidence that GIS vendors are working toward interoperability. "The OGC is really driven by the vendor membership," Limp said. "They see markets increasing. And they understand that if you take too long to get a specification out, then the market develops its own standards."
Consequently, with the Federal Geographic Data Committee (FGDC), the OGC has developed important specifications quickly. In August, the OGC announced that its members had agreed on two open interfaces that will let software access geospatial information on the Internet.
A Simple Solution
Last year, the OGC leaped toward resolving the problems of proprietary geospatial data formats when it agreed on the Simple Features Specifications for SQL, Object Linking and Embedding/Common Object Model (OLE/COM) and Common Object Request Broker Architecture.
Five products conform to the Simple Features Specification for SQL. Three of those are manufactured by Environmental Systems Research Institute Inc.: Spatial Database Engine for Oracle, SDE for Informix and SDE for IBM DB2. The other two products are Oracle Corp.'s Spatial versions 8 and 8i. Oracle8 is the regular database, and 8i is the Internet-enabled Oracle8 database.
Conforming to the SQL Simple Features Specifications has made GIS easier to use. "I can write a query to any OGC-compliant SQL database and get an answer back," said Sam Bacharach, Intergraph Corp.'s business development manager. "I don't have to write a query for each one of the databases I would connect to. I only have to deal with one kind of data coming back."
However, although Intergraph contributed to the development of the SQL Simple Features Specification, its professional GeoMedia product does not conform to it. Intergraph does not want to use the ESRI-developed and OGC-certified middleware product to get to an SQL database. Instead, Intergraph plans to conform to the upcoming OLE/COM Simple Features Specification.
ESRI's ArcInfo 8 product for geographers and cartographers, due out this fall, also uses COM objects. "It will have 1,200 COM components," said David Beddoe, federal OGC manager at ESRI.
However, ArcInfo is built in to ESRI's proprietary Avenue application development environment, and even the most devoted ESRI users are not taking the Avenue route. "We're primarily an ESRI shop, but we will no longer develop applications in Avenue," said Dave Wolf, the Environmental Protection Agency's geospatial data manager for enterprise information management. "It's all going to be in household names like [Microsoft Corp.'s] Visual Basic or nonproprietary like Java and C++."
Wolf is building a massive GIS system called EnviroMapper, aimed at delivering geospatial data processing functionality via the Internet. Instead of using Avenue, he is writing map objects as Dynamic Link Libraries, a de facto standard method of sharing functionality among applications.
Wolf said the EPA wants to share information and to develop systems that will interoperate. But he added that there is a continual need for communication among technical staff because code changes in one place affect code changes in another.
The Federal Emergency Management Agency also is grappling with changes in its approach to GIS. The agency's current GIS database is customized in MapInfo Corp. format. Like other GIS databases, it has no management system. Because another FEMA project, the National Emergency Management Information System, uses an Oracle database, FEMA chose to move to Oracle to maintain consistency, said Ed Corvi, manager of FEMA's Mapping and Analysis Center.
But Corvi said he did not want to switch without knowing that the database could handle spatial data. "We wanted a stable spatial component," he said. "A new combination that Oracle and MapInfo worked out made it worthwhile for us to jump into the Oracle database."
Oracle and MapInfo integrated MapInfo's suite of World Wide Web-based spatial and mapping products with Oracle databases to enable users to manage and analyze geographic data in Oracle8i.
FEMA plans to complete its prototype by the end of November while it builds an interactive mapping Web site for its Response and Recovery Directorate, which leads FEMA's disaster response operation.
The office now uses static maps in standard JPEG file format on its Web site. Corvi said he wants to use MapInfo's Java-based MapXtreme tool to develop Internet-ready spatial applications that will render the static maps interactive and customizable.
Lost in the Translation
However, Corvi and other GIS users still must translate from one GIS vendor's format to the format of another. Corvi uses MapInfo's translator to convert from ESRI's standard Shape files to MapInfo's Tab files and vice versa.
Ken Bristol, natural resource planner in the Range Environmental Planning Office at Eglin Air Force Base, Fla., also has experience using translators. "When we were taking data from agencies using ArcInfo, we had to use Arc Export uncompressed," he said. "It's like an ASCII file. [Document Exchange File] format is also commonly used." Bristol is primarily an Intergraph GIS user, but he also uses ESRI's ArcView and Bentley Systems Inc.'s GeoGraphics products, for example. "We use each one for its particular strengths," he said.
Although the depth and breadth of GIS translators has improved, they are not ideal. Users have to go through neutral file formats such as ASCII or DXF to accomplish the translation. It can take 48 hours to accomplish the translation, said George Korte, executive manager at Intergraph Federal Systems, Reston, Va. The user must export data from a source file, then import that file into the target system.
An Oracle manager agreed with Korte. "Data translation is not satisfactory for the kind of mission-critical applications our customers want to deploy," said Kirk Fisher, spatial solutions manager at Oracle Service Industries, Reston, Va.
To circumvent the translation process, Bristol is using Intergraph's GeoMedia software, which imports and exports data from different formats without the need for translators. "This is the result of the push toward open systems," Bristol said. "There was such a groundswell of support for open systems that vendors didn't have a choice. Customers were demanding it."
Bristol uses the system for infrastructure and natural resource management and for strategic planning. Metadata - data that describes the characteristics of other data - is another thorny GIS issue vendors are trying to resolve. The FGDC developed a GIS metadata standard called the Content Standard for Digital GeoSpatial Metadata to share, transfer, search for and automate geospatial metadata. Within the next year, it likely will become an international standard, said John Moeller, FGDC staff director.
Once approved by the international community, the CSDGM will provide consistent metadata documentation on an international basis. The FGDC also is working on a National Spatial Data Infrastructure, through which disparate data content standards can move toward interoperability. The standard could resolve the problem presented when, for example, an urban planner represents geospatial data differently than a forester.
"There are many data content standards being developed along themes, such as vegetation, soils and transportation," Moeller said. "Some have already been approved by the FGDC."
Jack Dangermond, ESRI president and chief executive officer, said his company's ArcInfo 8.0 product, set for release this fall, will implement the standard.
The OGC has kept moving at a steady clip. It is developing an architecture for geospatial application development that will provide the structure to map onto existing products' interfaces, said David Schell, OGC president.
If the rapid rate of progress in GIS continues, then it likely will pervade the mainstream unnoticed, as it becomes embedded in commonly used applications. "People are going to start to use spatial technology without knowing they are using it," said Steve Talbot, MapInfo's managing director for corporate development. "In fact, some people already are."
Gerber is a free-lance writer based in Kingston, N.Y.
The federal GIS user community and industry have made progress on interoperability standards, but significant problems still exist. The GIS community is tackling issues related to geospatial data management, incompatible data structures and disparate interfaces.Issues:
Users often must endure a time-consuming translation process to move GIS data from one vendor's format to another vendor's. Disparities between vendors regarding metadata, middleware and development environments continue to create complexities.Outlook:
Improving. The GIS industry last year agreed on specifications that will help resolve the problem of proprietary geospatial data formats and last month agreed on two open interfaces that will let software access geospatial information on the Internet. If progress continues, observers predict GIS functionality will increasingly become embedded in commonly used applications.