The need for earth science has never been more paramount. The devastating flooding of the Mississippi River this past year, strikingly portrayed on the cover and discussed in detail in this report (p. 37–42), was a sobering reminder of nature's elemental power. As a Nation, we face many environmental and economic challenges, such as natural hazards, that can be addressed effectively only through science. Water quality, resource assessments, climate change, and toxic wastes are all critical issues that can best be dealt with when approached from a sound scientific base. The goal of the U.S. Geological Survey is to provide hydrologic, geologic, and topographic information and understanding that contribute to the wise management of the Nation's natural resources and that promote the health, safety, and well-being of all Americans. FY 1993 has proven to be a particularly challenging one for the USGS. We entered into a time of transition from the long-term leadership of Director Dallas Peck and Associate Director Doyle Frederick to the appointment of a new director. We thank Dallas and Doyle for their many years of service and for their support during the transition.

As part of our transition efforts, we established a team of employees to examine USGS organization and programs and to develop a range of options for the incoming director. That team developed a revitalized vision for the USGS that will, under the guidance of our new director, move us positively and creatively into the 21st century. The vision of the transition team is that the USGS will continue its leadership in earth science for sustained global health, welfare, and prosperity. While the transition team was undertaking its important task, the dedicated employees of the USGS continued working diligently to address the many scientific challenges before them.

Much scientific good news from recent years came to fruition in many areas this fiscal year. The initiation of the National Water Quality Assessment program in 1986 signaled a profound change in our approach to water-quality studies. This perennial effort will give managers and policymakers consistent information on the status and trends of the quality of the Nation's vital water resources. This year we designated 20 new study units in 36 States for the second leg of what will ultimately be 60 study units that, in aggregate, will provide us with an overview of water quality in many of the Nation's most important river basins and aquifers. This year also saw the release of early findings from the National Synthesis component of the NAWQA Program. In response to questions raised during reauthorization hearings for the Clean Water Act, the NAWQA Program

provided information on the magnitude and extent of point and nonpoint sources of contamination in different parts of the Nation and their relations to different natural and human factors (p. 48,49). The results are an example of the type of information that NAWQA is providing that will be useful for making decisions about waterquality policies and programs at the national level.

We have moved aggressively into digital mapping and are making critical strides in building the National Spatial Data Infrastructure (p. 4-6), a key component of the information superhighway envisioned by Vice President Gore. Through our longstanding partnerships throughout the mapping world, we have been at the forefront of the transition from traditional paper maps to the exciting vistas of computer-generated maps.

We are reaping continued benefits from our intensive effort to map and explore the near-shore and offshore sea floor of the continental United States and the U.S. Exclusive Economic Zone. Boston Harbor, cited by the Environmental Protection Agency as the most contaminated harbor in the country, is benefiting from a cleanup effort that has as a key element scientific information from the USGS on the transport and accumulation of contaminated sediments in the bay area (p. 17-19). This type of information will be needed as the Nation deals with many coastal areas where the discharge of wastes into the ocean presents serious environmental and economic consequences.

In global change research, we are looking at the global carbon cycle and trying to determine the sources and sinks of this critical component in global climate and ecosystems. A key aspect of our global change research is reconstructing past climate "snapshots" in order to have a basis for distinguishing those changes caused by human activities from those caused by natural climate variation (p. 60–65). Reconstruction of these paleoclimates give scientists the means to test their climate models and improve their ability to predict future climate change.

These highlights are only a few of our many accomplishments during the past fiscal year. The year also saw the publication of the first standard USGS map produced by using fully automated computer technology. We developed a framework for assessing the economic benefits of new geologic map information in making land-management decisions. The EROS Data Center in Sioux Falls, S.Dak., which holds more than 2 million satellite images, was designated as the world data center for satellite images by the International Council of Scientific Unions. We identified high concentrations of agricultural chemicals in the Mississippi

River in the aftermath of the river's historic flooding, which dispelled previous notions about the dilution of herbicides in a large river system. Water managers in the Delaware River basin area are now using USGS information on the potential impacts of climate change on the river basin to more effectively balance water-supply storage against the movement of the salt front in the Delaware River. In conjunction with the National Science Foundation and the University of Colorado, we now operate the Nation's only ice-core repository in Denver, Colo., where scientists store and examine glacier ice to unlock information about ancient climates.

We are poised at a crucial and exciting threshold. Just as the need for science has never been more paramount, so, too, is the need to work effectively with other organizations to ensure that we meet the needs of the customers we serve, be they another government entity, an academic institution, or the public, whose taxes pay for our programs. The underlying theme of this annual report is that the USGS is at work across the Nation and around the world, conducting cooperative research and investigations in the earth sciences and disseminating traditional and innovative information products. Without the more than 1,200 other Federal, State, and local agencies that are our cooperators, the hundreds of academic institutions with which we interact each year, and the millions of people who rely on the USGS for maps, reports, data, and information, we would not and could not exist.

It has been my personal and professional pleasure to serve as Acting Director of the U.S. Geological Survey. It has been my good fortune to have had a very able Acting Associate Director, Bonnie McGregor, to share with me in the challenges and rewards of leading the USGS during the last 6 months. I have been repeatedly impressed with the breadth and caliber of science that is the constant climate of the USGS, and I commend each and every employee for their dedication. In concert with our many cooperators and colleagues, we are each day at work at the fundamental business of understanding our Earth and communicating that understanding to the public we serve. We look forward to the completion of the transition to new leadership for the USGS and to our continued commitment to provide the scientific foundation to help the Nation make wise decisions that provide for a safe environment and a strong economy. Enjoy reading the accomplishments of this, our 114th year of providing "earth science in the public service."

Robert M. Hirsch

Robert M. Hirsch

Acting Director, U.S. Geological Survey

National Map and Digital Data Production

The USGS continues to fulfill its

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responsibility to produce, revise, and distribute America's topographic maps, ⚫ which are available to the public through a national network of earth-science information offices and over 3,000 commercial map dealers. The recent explosive growth of geographic information system (GIS) technology has placed unprecedented * demands on the USGS for map data in computer-readable files. To accelerate the creation of a national, electronically retrievable cartographic data base, the USGS is working in partnership arrangements with public and private organizations to reduce Federal data-acquisition costs, minimize duplication of effort, and share "coverage," as in the mapping of a specific State.

Although certain segments of the public will always need printed maps (for example, recreational users, small businesses, and local government offices), demand will increase for specific types of USGS cartographic data in computerreadable formats. For example, aerial photographs used in map revision are electronically scanned, combined with digital terrain elevation data, and corrected for feature displacements due to variations in land elevation. Known as digital orthophotoquads, these information-age tools have significantly shortened the USGS map-making and map-revision cycles and are drawing substantial interest from GIS users. Other computer-data products available from the USGS include digital files of map lines, elevation, land use and land cover, and geographic names.

Digital image of the Denver Federal Center.

features, and boundary and Public Land Survey System (PLSS) information, all of which are vital data for a variety of planning and management applications. The USGS's topographic maps and resulting digital line graphs are the most comprehensive set of base cartographic information available to the Nation's resource managers and scientific community.

In response to the exponential growth in demand for its products, the USGS has developed a three-pronged approach to meeting the diverse needs of its customers:

• Printed maps: The traditional map user remains a valued customer. The USGS sold approximately 5.5 million maps during FY 1993. Demand should remain stable into the 21st century. • Digital line graphs (DLG): DLG's are topographic maps in digital form and reflect the same level of information shown on printed maps. DLG's are often the foundation on which geographic information system (GIS) users orient other types of data.

• Digital orthophoto quadrangles (DOQ): The goals of the National Aerial Photography Program (NAPP) are to complete conterminous aerial photographic coverage of the United States and to provide cyclic updates every 5 years. The DOQ process brings spatially corrected photographic images acquired by the NAPP into computers, where the data can be combined with other digital map data (such as roads, boundaries, and hydrography). DOQ's provide an economic,

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The Public Land Survey System (PLSS) was established by the Second Continental Congress in 1785 to facilitate the orderly settlement of that part of the United States acquired by the Federal Government by cession from the States, by treaty, and by purchase. The PLSS currently provides the basic ownership (cadastral) reference system for all States except for 18 Eastern States, Texas, and Hawaii. Public lands are subdivided by a rectangular system of surveys established and regulated by the Bureau of Land Management. The standard format for subdivision is by townships measuring 6 miles on a side; townships are further subdivided into 36 1-mile-square numbered sections.

A CTL staffer at work in the Cartographic Technology Laboratory.

For more information, contact: Telephone (303) 236-5825 Internet rolsen@usgs.gov

high-resolution image base for use in map revision.

A major revision program known as the digital revision and product generation (RevPG) system will provide current, reliable information to its users. The primary components of the system are customized commercial GIS software and distributed workstation technologies.

During FY 1993, the RevPG system was used to revise the first topographic maps that used DOQ's as the primary source of information. The RevPG process provides users with a DOQ on which to delineate discipline-specific information. It creates updated DLG's for the National Digital Cartographic Data Base, which are valuable for the spatial integrity and multiple-user versatility that they provide, and can also be used to produce an updated printed map from the revised DLG's. The RevPG process provides a mechanism through which the Nation's spatial data user community can acquire cartographic information in an effective, efficient manner.

Randle W. Olsen

is chief of the USGS Rocky Mountain Mapping Center in Denver, Colo.

Cartographic Technology Laboratory Opens

The

he Cartographic Technology Laboratory (CTL) opened in April 1993 to enable USGS cartographers and researchers to develop advanced digital cartographic production processes and applications. Located in the National Center in Reston, Va., the CTL houses the latest in digital cartographic hardware and software.

The CTL promotes mapping research and modernization efforts by pursuing advanced developmental and applications projects in spatial data collection and analysis. Projects currently under development include the National Advanced Remote Sensing and Applications Project, an exhibit of USGS data sets for the Washington, D.C., area, and three-dimensional visualization of the Earth's surface.

The CTL supports research and development in image-processing techniques, digital revision, product generation, digital line graph-enhanced data format, softcopy stereo extraction and analysis, land-use and land-cover production, evaluation of other mapping organization digital spatial data, and geographic information systems applications. The CTL also supports production activities of the Mapping Applications Center.

The CTL staff demonstrates software and production techniques developed by the USGS and makes commercial software and data products available for use. These products range from software available on personal computers to those used on complex workstations.

The CTL provides briefings and demonstrations of production capabilities and developmental activities to visitors and employees. In 1993, visitors to the

The Mapping Applications Center, one of five such centers in the USGS, manages the National Digital Cartographic Data Base and the National Mapping Program's map printing operations, using advanced technology to create new map production techniques, processes, and products.