A Few new GIS and enterprise technologies
Jack Dangermond Environmental Systems Research Institute, 380 New York Street, Redlands CA 92373-8100 U.S.A. Abstract The pace of development of both communications and computer hardware and software capabilities continues to be quite rapid, resulting in a number of new technologies for GIS (geographic information system) and enterprise information systems. One of these is technology for performing rapid spatial queries on information stored in standard relational databases either within an organization or on servers scattered across a network. Another is object technology for embedding GIS capabilities in new or existing applications on desktop computers. A third is the ongoing development of new GIS-related capabilities for the Internet and World Wide Web (WWW), including componentized GIS capabilities and metadata standards. Other technical developments are also important. All these recent technical developments are about to make profound changes in the way in which GIS can be applied to AM/FM. By spatially enabling enterprise information systems they will leverage AM/FM investments made over many decades in some of the largest information warehouses in the world. They will pave the way for AM/FM spatial information resources to flow on the Information Highway which the Internet and the National Spatial Data Infrastructure (NSDI) will soon provide. The implications of these changes are discussed. Introduction More and more organizations are recognizing that their data are closely linked to location; as a result they are moving to apply GIS to their mission-critical operations. As AM/FM-using organizations develop and use GISS they face various problems common to most of today’s information technology organizations, such as managing increasingly large databases with increasingly diverse data types, providing enterprise-wide access to the organization’s data, meeting the needs of increasing numbers of casual users, working in expanding clientiserver networked environments, and providing information via the Intemet. The capabilities described here were designed to meet some of these needs. Processing Spatial Data in Standard Relational Databases Many organizations have very large quantities of data stored in relational database management systems (RDBMSS). The data structures of these RDBMSS are increasingly being extended to provide common means of access to a wider variety of data types, 123.including spatial data. Such developments mean that spatial information can be brought into the computing mainstream of standard, transaction-processed databases and that organizations can combine their management information system (MIS) and their GIS in a single relational database. For organizations such as utilities, however, these databases are very large, often in the range of tens to hundreds of gigabytes or more, and while the speed of transactions with the database have been acceptable for text and numeric data, until recently most transactions with spatial data have been much slower, often “long transactions,” requiring minutes or much longer periods of time for execution. Fortunately, a new data processing engine technology has become available which makes a wide variety of management and analysis operations on spatial data about as fast as transactions on other forms of data. This technology has been termed a spatial database engine. It operates in a standard client/server environment, and resides on both client computers (including desktop PCs) and server computers. The software is based on open system design principles. The spatial server is optimized for queries (both conventional SQL and spatial queries) and retrievals, and provides extremely fast system response times (a few seconds), even with hundreds of simultaneous client users. This functionality was designed for AMIFM and other large organizations in which very large RDBMSS reside on mainframe computers which are accessed by hundreds or thousands of users. This new technology provides standard software tools for spatial data management and a wide range of geoprocessing tools is available to programmers and users. Geographic features are represented in a geometric data model, complemented with relational database data types (e.g., integer, date, BLOBS, etc.) for representing attribute information. The data model is feature oriented: geometric data and associated attributes are stored together and a single disk access retrieves both. The technology is designed for use by system developers and integrators, providing them with the tools they need to construct custom applications to meet a wide variety of specific needs in enterprise, client/server, networked environments. It is a large set of spatial operators together with a spatial application programming interface (API). This technology’s functionality can be built into applications in ways which are transparent (invisible) to the user, minimizing the need to educate users on GIS technology. By providing familiar kinds of access to new classes of data, this kind of data processing engine technology can expand the range of applications for corporate databases as well as leading toward development of next-generation spatial objects and data types. Embedded Object Technology Among the successes of object-oriented technology has been its use in the rapid development of custom applications and custom user interfaces through the use and reuse by software and application developers of various kinds of interchangeable software components. By enhancing the speed and reliability of application programming, such 124.object technology has been especially useful to AM/FM organizations engaged in rapid prototyping and development of new applications in such areas as system design, emergency response, and call-before-you-dig. A recent GIS software development makes use of this approach; it is a set of object-oriented tools which supports a building block approach to the rapid development of mapping and related GIS applications. A variety of components have been developed which provide such GIS capabilities as desktop mapping, data display, handling of images and multiple map layers, SQL query, spatial analysis, GPS connection, data publishing on a network, and the like. These components can be used with Visual Basic, C++, and other common software development tools to rapidly build custom, object linking/embedding (OLE)-compliant applications, or to add GIS functionality to existing applications, such as spreadsheets or databases. The components are programmable OLE automation objects which work with OLE custom controls (OCXS) to permit embedding of GIS functionality in Microsoft Windows applications. They meet the intent of the Open GIS Consortium with respect to GIS fimctionality. The components provide an application development environment which permits the embedding of dynamic map displays in all kinds of Microsoft Windows programs, and which greatly reduces the programming needed to deliver customized applications. Component Object Technology for the Internet/Intranet A related technology has also recently become available for those who want to develop GIS capabilities for new or existing Internet and World Wide Web applications. Advances in HyperText Markup Language (HTML) and the introduction of Java and Active X now allow not just text and images but also active content to be accessed and interacted with over the Internet; this advance can be applied to permit interactive mapping and GIS functionality: databases can be published on the Web; client computers can make requests for information, analysis, and maps; and existing applications can become spatially enabled. This component technology is available on a variety of system architectures, for one or many servers, and permits the monitoring of system performance and the efficient brokering of client requests through request brokering architecture. The component technology provides many mapping and GIS fictions; uses standard HTML-based Web browsers such as Internet Explorer and Netscape Navigator, including ActiveX controls and Java applets; and supports standard inforrnatiordcommunication servers. Data formats include various commercial GIS data formats and many image formats. 125.The result is a cost-effective means of sharing spatial information in customized applications within an organization’s intranet, or sharing worldwide on the Intemet, Metadata Standards Of course, as these and other recently developed GIS-related tools become more widely used, and users increasingly want to access spatially-referenced data, it is essential that better information about the spatial data in the databases be made available. At the present time a good deal of effort is being put into the development and implementation of metadata standards and the means for organizing such metadata and accessing it, especially by means of communications networks. Applications The availability of these new technologies will facilitate some existing AM/FM applications of spatially-referenced information and will open the way for new applications as well. The ability to treat many applications of spatial data as transactions against a database should allow wider use of spatial data for AM/FM, allow the leveraging of the investments already made in spatial data, and improve the accuracy and timeliness of the use of such data at all levels of AM/FM-using organizations. GIS has proven useful for policy-making, planning, monitoring, decision making and management, and making it easier and faster to apply should be helpful throughout organizations. Spatial engine technology should make it easier to make data available to those dealing directly with customers in many areas including demographics-based marketing, trouble calls, incident reporting, and call-before-you-dig. By speeding responses to requests for spatial information and spatial analyses, the engines may facilitate responses to system failures and assist during the management of emergencies. By creating easy-to-use interfaces, the use of componentized object technology should facilitate use of intranet and Intemet access by government regulators and other government staff, customers, the general public, and others who might be granted some access to AM/FM databases for such purposes as regulatory compliance, environmental monitoring, and providing responses to proposed development plans. Easy-to-use interfaces, especially where the spatial-operators can be concealed from users, will also make company staff more willing to use information systems. As a result, it maybe possible to think about increased data sharing with outside individuals and organizations. This may provide many benefits. Giving people access to more information about proposed routes, the location of new facilities, or the information on which decisions are based, may head off delays caused by opposition to planned development where that opposition is based on incorrect perceptions or misunderstandings. It’s possible that providing more information, more readily, to 126.customers and the public, and so helping people better know the utility serving them, will be one way for utilities to meet competition from other service providers. For some kinds of utilities, such uses of the Internet may become a key to expansion and profitability. | ||
|
|