long time, the Geological Survey was one of the best customers for its topographic maps, as it remains today. Now, however, there are many more Federal, State, local, and private customers who make a wide variety of uses of Geological Survey maps. Maps are their tools for making important decisions regarding vital and diverse public issues, such as management, coastal wetlands inventories, transportation, energy, conservation, resource estimates, flood insurance, civil defense and emergency preparedness, agricultural lands conservation, environmental protection, and many others. Just deciding what to map and how to map has become a complex process of widespread consultation and tough priority assessment.

At the same time, public policy and customer needs have expanded the scope of mapping; technology has similarly affected the nature of information people need and the methods for providing and using it. It is a highly interactive process. Public policy places demands on agencies, and they attempt to respond more quickly and fully by applying advanced technology. In turn, the Survey responds with different and innovative ways of surveying, collecting map data, compiling it, and providing it. New methods are also applied internally to speed and to improve the mapping process. Automated equipment delineates information on compilation sheets, aerial photographs are processed in new ways to derive terrain contours, and the new information produced by these processes is itself applied by customers to their own needs.

These are the forces of the cartographic revolution-public policy, changes in customer usage, and technology-coming together in a time of transition to change fundamentally time-honored ways in which cartographers have clarified, portrayed, and communicated things that describe the Earth.

THE DIGITAL
CARTOGRAPHIC
REVOLUTION

In responding to public policy changes and customer demands for

cartographic information and products, the Geological Survey has evaluated its traditional methods of response. Out of this reevaluation has come a realization that increasingly sophisticated and technologically advanced customer demands require the Geological Survey to respond with a great deal more than traditional line maps. That "great deal more" is digital computer technology through which the Geological Survey can collect, organize, and disseminate cartographic information in ways suited to emerging uses of data in customers' own systems of analysis and management.

For much of the history of computer development since World War II the technology was too expensive and too limited to be economically applied to the enormous information content of cartographic products. This is no longer the case. Computer technology has become very inexpensive, as is exemplified by small calculators and electronic games in the home. One consequence of the widening influence of computer technology among map users is a rapid change in their need for cartographic information. At one time, a map, periodically revised, was enough, but this is no longer so. Major units of Federal and State Governments require information from maps that can be integrated into their own computer-based systems:

• The Forest Service uses terrain data in digital form for predicting likely paths of forest fires.

• The Federal Aviation Administra-
tion is using digital informa-
tion on possible obstructions
around airports (towers, moun-
tains, tall buildings) for inte-
gration into obstacle-avoid-
ance landing systems on board
airliners.

Energy agencies at Federal and
State levels use many types of
map information for integra-
tion into computer-based
systems for assessing environ-
mental and conservation
issues.

• Federal land management
agencies, such as the Bureau
of Land Management (BLM)
and the Forest Service, are
looking to the Geological
Survey for critical categories

of map information for use in natural resource inventories. • Terrain information expressed in digital form, boundaries, and land nets will help improve inventories of the Nation's natural resources, from important minerals to grasslands and from coal beds to important farmlands.

• To help protect wildlife, map data in computer form will help locate habitats so that they may be protected.

• Map information in digital form will also serve needs beyond the Nation's physical resources. To assist the Bureau of the Census to inventory America and Americans, the Geological Survey will be preparing boundary information from maps in digital form. These maps will help organize census information more quickly and accurately, which is of critical importance to a wide variety of social programs whose funding through political subdivisions is linked closely to census information. These are but a few of the new and sharply increasing customer needs for digital map information-information in forms that may be integrated into computer-based systems of management, control, inventory, and analysis.

For some customers, a printed map will remain the answer to their needs. For others, data from parts of the cartographic process will be the answer. Some products will be in the form of pure digital information, while others may be in the form of analytical services. Still others may be in graphic formats that can be manipulated.

This emphasis on information from the entire cartographic process, with each part taking on distinct uses for customers, will mean a major transition for the Geological Survey over the next decade. The Survey will move from the task of preparing maps as the one final product to the task of creating and maintaining a national digital cartographic data base from which many intermediate and final products, analyses, and services will flow to customers.

This digital cartographic data base eventually may allow some customers

to design their own products by taking information from the Suvey's data base, combining it with information of their own, and portraying it their way. An example of how conventional maps and other information already are used in this fashion is illustrated by the coal folio program.

The coal folio combines a variety of different information with 1:100,000scale map bases for showing coal beds, overburden thicknesses, and reports on geochemistry of soils, water, and rock. It includes data on surficial and bedrock geology, geologic hazards, and engineering criteria needed for soil and rock stabilization analyses in connection with construction and mining. Customers are able to combine compatible Geological Survey land use maps for areas covered by the coal folio. Survey's hydrologic maps may also be integrated with the folio data base. BLM is converting surface- and mineral-ownership data to the Geological Survey's 1:100,000-scale map base so that it, too, may be integrated with the system. The broad effort will enable the Department of the Interior to improve substantially its management of the Nation's Federal lands.

The future for applying digital data, on the other hand, is illustrated by

the National Coal Resource Data System. It is an interactive computer under development by the Survey that will quickly report the information about coal resources on either an area or a specific site basis and show it graphically on a base map or as an overlay. It has much of the information a manager needs for helping people develop the wise use of this important resource, including, for example, longitude and latitude (positions), political boundaries (ownership), terrain data, and point-source (specific site) information on coal, outcrops, mine workings, drill holes, and chemical and physical parameters of the coal. Much of the system's cartographic data is used in digital form to help analyses, as well as display of information.

These two systems illustrate the more responsive ways in which Earth resources information may be provided and how digital cartographic data will work in the future on an integrated and compatible basis with other kinds of information.

Interchangeability and compatibility of different data present the Geological Survey with a difficult challenge. In the past, cartographic information was viewed primarily for use in compiling a particular series of maps. But now and tomorrow, the information

must be applied to a wide variety of other products and services.

Consider the benefits that might accrue from the ability to integrate such diverse data as weather, terrain, and rivers from satellites and other sources which could combine both fixed and rapidly changing information. Civil and emergency preparedness is an obvious example of a critical area that can benefit. Digital cartography will allow information from a natural or manmade disaster to be combined, as it occurs, with fixed cartographic and other data. Were a nuclear plant to leak radiation or a hazardous cargo to be accidentally dumped, weather and topographic information could be combined with site data to predict the spread of danger. This kind of prediction is already being done by the Geological Survey. Similar calculations are made to project the trajectory of oilspills as a part of analyzing potential environmental hazards associated with spills at proposed offshore leasing sites.

By combining stored cartographic data with other information, public officials could portray events in ways that would allow people to act more quickly and more wisely to save lives and property. The opportunity will be rich for the production of maps that

would be dynamic, reflecting temporal phenomena, and from them allow people to predict future phenomena. Such dynamic maps could even be transmitted directly into people's homes and offices as is now done with satellite weather data. The prospect for using such diverse information focuses attention on the entire process of interagency and intergovernmental coordination and cooperation in collecting and maintaining digital cartographic information. In the past, the Geological Survey, as coordinating agency for Federal mapping, has met with other Federal agencies to assess their mapping needs so that priorities for new mapping and map revisions could be set. The process has grown in importance, and, today, a large number of Federal, State, and local units of government are canvassed in setting priorities.

The future, though, will require far more than setting priorities for map production. It will mean coordinating the development and acquisition of cartographic information, setting standards for its accuracy and use, and seeing to its widest possible compatibility with diverse public needs.

THE MANAGEMENT

CHALLENGE

The cartographic revolution poses two management challenges to the Geological Survey. One is to mobilize information resources from within the Survey and from other Federal, State, and local agencies of government. The other challenge is to create a comprehensive data base for cartographic information with procedures for its widespread and multipurpose use.

Mobilizing information resources primarily challenges the Geological Survey's ability to foster a willingness to cooperate and to share throughout all levels of government. Many public agencies, particularly those responsible for land and resource management, produce large quantities of information, some of which is cartographic and may be well suited for inclusion in the cartographic data base. Much other information can be

made far more useful if it can be combined with standard digital cartographic data.

Both cases require that information be in some ways compatible and that it be in forms or formats which encourage its multipurpose use. Achieving compatibility and standardization to some degree across organization lines and among many Federal and State agencies is a formidable task. In creating a comprehensive data base, the Survey will emphasize organization and content that encourage widespread and multipurpose use-a data base that is also a service network. Its successful creation will depend on (1) data acquisition, (2) digitizing of graphics, (3) data-base management, (4) development of new computer-generated graphic products, and (5) customer services, including technical assistance to help people apply advanced technologies effectively.

Data acquisition will include collecting and updating various categories of information in the data base. It will have an interesting influence on the Geological Survey's historic view of map revision, which has meant revising all necessary data categories within a map quadrangle. But as the Survey moves into digital cartography, the focus of revision will shift from specific map quadrangles to sets of data on a geographic basis. Acquiring data from sources other than the Survey's own field, scientific, and aerial surveys will contribute important classes of information, such as transportation and boundaries. Agreements will be established with other agencies so that data may be provided regularly and in proper formats. It will be a formidable task. The quality of data varies substantially from one place to another. Computers are unforgiving-they do not gloss over errors. And while organizations may compromise their differences or leave some things to another time, computers do not.

Important categories of information will continue to be collected directly by the Geological Survey. It is likely that the agency will prepare themes and data extracted from images obtained from both aircraft and spacecraft. And, of course, contour and elevation data will continue to be produced.

The second area of activity will be translation of visual-graphic-information into digital data. During the 1980's, the limited amount of graphics digitization now being performed will grow substantially as data is entered directly into the base from existing maps.

It is a necessary phase to build a data base from a valuable existing source of information, primarily the maps themselves. The ability to enter data directly from graphic sources is also important for another reason. Much cartographic information is graphic in its initial character-aerial photographs or line networks of one kind or another.

Promise of computerized or digital cartography will depend on a third important area of activity new to the Geological Survey-establishing and managing a massive national computer data base. It may contain in storage as much as several billion bits of data. Some scientists estimate the amount of data even higher. Which estimate one accepts depends on assumptions about the resolution or level of detail people will need. This data base is now being started at the Geological Survey by digitizing data from the 1:24,000-scale 7.5minute topographic quadrangles.

The fourth area of activity, graphic products, opens new opportunities to apply cartographic information. One application might be automating preparation of plates used in printing maps. Computer-driven plotters already prepare some map overlays. In a few years, automation of other map compilation processes directly from the data base may enable the Survey to produce press plates automatically. Combined with other techniques, it could considerably shorten the 4 to 5 years it now takes from aerial photograph to printed map. The ability to automate the process of creating map graphics will also mean that more unusual or oneof-a-kind maps may be produced, bypassing what are now timeconsuming and expensive manual steps.

The fifth area of activity, customer service, represents yet another area of change for the Geological Survey. In the past, service was primarily linked to product availability, helping customers find the maps they need.

In recent years, the activity has expanded to include creating a central resource through which people could identify not only the maps they need but also aerial photographs and satellite imagery, individual map feature overlays, and a variety of other items from the mapping process itself to indexes and catalogs of cartographic information.

In the future, customer service will include technical assistance to help people apply cartographic information. Geological Survey representatives not only will help people find the information they need, they also will be able to aid other government agencies in applying that information to their own needs.

Data acquisition, graphics digitization, data-base management, graphic

products, and customer service will be the major activities of the digital cartographic data base and network. They will be the key activities of the National Mapping Program by the 21st century.

Yet with so much change taking place, with so many new and revolutionary technological innovations to be applied, some things will remain the same. The same three fundamental assumptions about mapping that have guided the Geological Survey for a century will remain as valid as in King's and Powell's time.

Mapping the Nation is crucial. Wherever a decision must be made regarding the public welfare and national treasures of land, water, and minerals, people will continue to turn to maps for guidance. People will

continue to demand maps and new cartographic data that meet the highest standards of scientific validity and technical accuracy. People will continue to expect maps to clarify as well as to portray and to communicate to a broad spectrum of customers and to cover a wide variety of uses.

The digital cartographic revolution does not change these old assumptions. It is a reassertion through renewal of their lasting importance. In a world of increasing complexity and technological sophistication, the cartographer's ability to clarify and to portray from myriads of data, to show the relationships among the things of the Earth and the effects of people upon them will help as never before to know the Nation better and to preserve and to protect its legacy of treasures for centuries to come.