description language that conveys this spatial information to a variety of printers and other high-resolution image setters. A non-GIS software system called TELLAGRAF was used to create the time-series graphs in the drought illustration. TELLAGRAF also operates on the USGS DIS computers and has a PostScript output format. The horizontal and vertical coordinates of the block of time-series graphs in the Adobe Illustrator 3.0 layout then were incorporated in the TELLAGRAF file. The PostScript files of the block of time-series. graphs and the maps and illustration explanation then were merged to create the digitally mosaicked illustration. The DIS image setter produced the high-resolution prescreened negatives of the mosaicked illustration used in printing the NWS report. The highly automated illustration-preparation process was used to prepare 52 drought illustrations (one for each State, Puerto Rico, and the U.S. Virgin Islands) and 52 flood illustrations, which have a design similar to the drought illustrations. The illustration-preparation process used in the NWS reports relies extensively on computer-assisted procedures for manipulation of data. The human touch and creative eye are still important in the preparation of illustrations, but the large number of illustrations for a typical report could not be prepared efficiently without extensive use of GIS and other computer technologies. The increasing use of GIS in support of NWS reports has paralleled the implementation of GIS technology within the USGS. The preparation of NWS reports has identified and led to the solution of many GIS problems, such as data accuracy standards, documentation, archiving, and distribution of geographic data. GIS-based illustration production methods have progressed from simple ink-pen plots of geographic linear data to the creation of prescreened color-separated negatives for point, line, and areal data. GIS technology is integral to the analysis of data and the planning for future reports. Specific problems concerning the manipulation and extraction of thematic information from hydrologic data bases have been solved, but the integration of symbolic hydrologic data and text wholly within a GIS system to prepare NWS illustrations still remains to be fully defined and implemented. The use of GIS techniques will continue to improve the content, quality, and efficiency in the preparation of illustrations. The GIS techniques that have been developed for the preparation of multicolor NWS illustrations are being documented and distributed so that these techniques can be used in preparing other USGS publications. GIS-A Pioneering Approach to Regional By John Michael Kernodle and U nder the USGS Regional Aquifer-System Analysis (RASA) program, geologic, hydrologic, and geochemical information are assembled and analyzed to develop an understanding of the major ground-water systems in the United States. The RASA program provides quantitative information that enables Federal, State, and local water-resources officials to effectively manage aquifer systems. An important element of the RASA studies is the use of computers to simulate ground-water flow, both to develop an understanding of the natural hydrologic system and any changes caused by human activities and to provide a method of predicting regional effects of future pumping or other stresses. The San Juan Basin RASA study area covers about 19,500 square miles along the eastern edge of the Colorado Plateau in New Mexico, Colorado, Arizona, and Utah (see figure, facing page, top right). The principal uses of water in the basin are for municipal, industrial, domestic, and livestock purposes. Surface water is fully appropriated and ground water is the only source of water supply in much of the basin. The study area is defined as that part of the San Juan structural basin that contains Triassic through Tertiary rocks. The San Juan Basin RASA was the 20th of 25 studies in the RASA program, but was the first to use GIS technology to accomplish the major objectives of the study. These objectives were to define and evaluate the basin's aquifer systems, assess the effects of ground-water use on aquifers and streams, and determine the availability and quality of ground water. Traditionally, the results of RASA studies have been published as USGS Open-File Reports, Water-Resources Investigations Reports, Hydrologic Investigations Atlases, and Professional Papers. The final results of the San Juan Basin RASA will be published as Professional Paper 1420. In the interim, however, 10 Hydrologic Investigations Atlases (HA-720 A-J) have been published. These atlases describe the geology, hydrology, and geochemistry of major hydrogeologic units in the San Juan Basin. The GIS data bases used in the preparation of these atlases serve dual functions: cartographic bases for thematic illustrations in the atlases and data for input into ground-water-flow and geochemical models. Publications created with GIS technology are not just maps and words; rather, they are a form of reusable data that document areal geologic, hydrologic, and geochemical interpretations. By using GIS, both the areal hydrogeologic information and the finite-difference model data can be constantly revised until the very last phases of the investigation. The GIS applications used in the San Juan Basin RASA saved labor, time, and money. Compared with limitations encountered during many hydrologic investigations, such as relatively short project length, limited funds, and induced deadlines, the San Juan Basin RASA was unique. For example, the project spanned more than 5 years; funding was adequate; deadlines mainly were internal and self-imposed by the project staff; and the study was continually well staffed. Taken in context, these factors enhanced the benefits of using a GIS during the San Juan Basin RASA, which include problem analysis that previously would not have been possible using traditional methods. Several digital data bases and their resultant GIS data layers were created during the San Juan Basin RASA, and different amounts of time and labor were required to produce them. For example, the digital base map was produced in about 1 year. Digitizing the basinwide geologic map required about 6 months of continuous labor and even more time to check the work and code the geologic units. Acquisition of a commercially available oil and gas test-well data base and associated geochemical brine data base required about 4 months. Ongoing acquisition of other data bases, such as basin topography, land ownership, and precipitation took several months. In addition, because GIS was a new and continuously evolving technology, the training of project personnel in the applications of GIS and other digital techniques was a constant consideration. Once the GIS data bases and layers were in place, the true benefits began to be realized. One benefit was the development of an accurate base map for the study area that can be transferred with accompanying thematic data into the formats and media that meet USGS publication standards. Another benefit was the development of interfaces with additional analytical software and data bases that are maintained by other public agencies and private firms, which makes the data from the San Juan Basin RASA more available and useful for the officials and managers who need the information. In addition to simple datatransfer mechanisms, these interfaces have been used for analysis of the occurrence of oil and gas in the San Juan Basin, analysis of the top of hydrogeologic units in the subsurface, regression-analysis of surface-water runoff An active, cratered travertine spring mound along the southeastern margin of the San Juan Basin. Saline ground water discharges at a rate of about 10 gallons per minute to the land surface from late Paleozoic and Triassic strata after migrating upward through fractures associated with a major reverse and thrust fault zone. Top, The central cratered part of the mound encircled by a travertine rim. The crater is about 40 feet in diameter and at least 50 feet in depth. Bottom, The arcuate travertine mound (about 50 feet in height), discharge of water from the crater rim on the right side, and recently deposited travertine (marked by light-colored areas on the mound slopes). STEVEN D. CRAIGG JOHN MICHAEL KERNODLE and ground-water recharge, and analysis and GIS presentation of data from the groundwater flow model. A third benefit was simply a reduction in time and effort needed to create groundwater flow-model-input data sets. A minimum of 14 hydrogeologic units needed to be represented in a ground-water flow model of the aquifer systems in the San Juan Basin. If the model simulations were restricted only to one finite-difference representation of these 14 units, more than 1.4 million manual data entries would be required, which would have taken at least 100 uninterrupted 8-hour workdays of continuous data entry just to prepare data input for each version of the groundwater flow model, excluding time to verify the accuracy of the data entry. A preliminary model of the Gallup Sandstone, Dakota Sandstone, and Morrison Formation part of the flow system had been prepared in 1987; the Hydrologic Atlases for these units were in review, and therefore the GIS data bases for these units were available for construction of the ground-water flow model. From these and other GIS data bases of outcrop, thickness, and altitude of the top of the aquifer, and of precipitation, topography, and hydrography, a steady-state groundwater flow model was constructed in 2 days. The expanding data bases are not limited to the study area of the San Juan Basin RASA. The GIS data bases have encouraged a freer exchange of information between other agencies and the public. The free exchange of information in a common format is reason enough for using the GIS; however, because the areal coverage from the shared information greatly exceeds the area covered by the San Juan Basin RASA, the expanded data bases also are serving as the basis for new GIS-based investigations in other parts of the Southwest. A GIS and its associated data bases are not end products. Rather, the various data layers are used as input to digital groundwater flow models of basin aquifer systems and as input to geochemical models of rockwater interactions. For the San Juan Basin RASA, the new GIS technology accomplished a traditional task more efficiently and resulted in increased productivity. Tasks that were once considered to be too labor intensive, impractical, or impossible when traditional methods were used can now be accomplished with the aid of a GIS in a timely and costeffective manner. Cooperation-The Key to Unlocking the Benefits of Geographic Data By Michael A. Domaratz Abro emergency preparedness and response. . .global monitoring and modeling...economic development. . .intelligent vehicle and highway systems...agricultural pest management... water-quality assessment. . .range and forest management...crisis management...mineral, oil, and gas leasing...wetlands analyses. ... census taking.. .facilities siting...mapping and charting... mail delivery...all of which require accurate and reliable geographic data for solutions. Government agencies are being asked to respond quickly in addressing these problems. To add to the complexity, new and growing administrative and regulatory responsibilities have placed tremendous pressure on information delivery systems. Geographic data sets, such as environmental, natural resources, and socioeconomic data, can be used to understand national problems and to unlock answers. Computerized technologies for handling geographic data, such as GIS, have emerged as highly efficient and effective tools for solving complex issues. Federal agencies have realized the advantages of these technologies. More than 95 Federal organizations use these technologies in a variety of applications such as those listed above. State and local governments and private companies also are actively using geographic data in applications such as governing land ownership and use, locating sites from which to provide services, routing vehicles, maintaining public works, managing land, and marketing products. The Nation must act quickly if it is to maximize the benefits of using this technology. These powerful technologies are acutely dependent on the availability and quality of computer-readable, or digital, geographic data. Development of the needed digital geographic data is invariably the largest cost factor in computer-assisted analysis of complex issues. With billions of dollars being invested in geographic data and related technology by Federal, State, and local governments and the private sector, interest in means of reducing costs and duplication of efforts to increase the return on this national investment has grown quickly. Many decisions on these investments will be made over the next few years, and it is With these concerns in mind, the Office of Management and Budget issued a revised. Circular A-16, Coordination of Surveying, Mapping, and Related Spatial Data Activities, in October 1990. Such circulars establish governmentwide policies as well as responsibilities for implementing these policies. A major objective of revised Circular A-16 is development of a national digital geographic information resource. As an analogy, just as the connectivity and standards of the Nation's electric power distribution network provide benefits of increased convenience, markets, and economies in generating Data categories coordinated under the revised Office of Management and Budget Circular A-16. These categories form the data foundation for many applications of geographic data. |