geophysicists, and petroleum engineers from Conservation Division Regional Offices prepare range estimates or point estimates on a number of geologic and economic factors that are needed to estimate the potential value of each tract. These values are then analyzed by computer program. In the evaluation of tracts, just as in basin appraisal, the estimation of each factor involves some degree of subjectivity. The evaluation results are presented as probability distributions, and a determination is made of the most probable or statistical mean value. These tract evaluation results are used by BLM to determine if industry bids are acceptable for a lease on a given tract. These estimates, for obvious reasons, are not made public prior to the sale.

The terms and conditions of each lease sale are published in the Federal Register as a final notice of sale not less than 30 days prior to the date of the sale. Leases are usually sold on the basis of a cash bonus with a fixed one-sixth royalty or a cash bonus with a fixed sliding scale royalty determined by the amount of production. A small yearly rental of $3.00 per acre or a fraction thereof is assessed on nonproducing leases. At the lease sale, all sealed bids are opened and publicly read. Following the public opening, all bids are checked for technical and legal adequacy, qualification of bidders, sufficient advance bonus (20 percent at the time of bidding), powers of attorney, compliance certificates, and bonds. Acceptance or rejection of bids is not made until after the postsale analysis and a Department of Justice review.

Leases are issued or rejected based on an analysis of how the action on each individual tract relates to the Department of the Interior's policy on receipt of fair market value. Timely resource development is a prime consideration in scheduling the sale in the first place as are concerns for the environment. The environmental aspects of each tract, including opinions expressed at the public hearings, are discussed individually in the EIS. Orderly development is also discussed in the EIS and at public hearings. Estimates of resource economic value are made independently prior to the sale and express the Department's own opinion of lease value. All of the information described above, plus an analysis of conditions at the time of the sale and indications of competition expressed during the sale, are used in determining if a lease should be issued to the highest bidder.

If the high bid on a lease tract is found to be acceptable, BLM issues a lease to the successful bidder. Upon issuance of the lease, the remaining 80 percent of the bid price and the first year's rental becomes due.

FUTURE DIRECTION

The Department of the Interior is developing a new 5-year lease schedule for 1980 through 1985. Sales in six frontier areas occurred during the 1975 to 1980 lease

sale schedule, and 78 exploratory wells have been drilled. Although additional wells are now being or will be drilled to further test some of these leases, the results of the first 78 wells in terms of the discovery of oil and gas have been discouraging.

Much of the drilling in frontier areas to date has been focused in the Baltimore Canyon trough, the Gulf of Alaska, southern California, the southeast Georgia embayment, and the Lower Cook Inlet where major structures were the principal targets. The results in the Gulf of Alaska were particularly discouraging, but only a small portion of that area was actually tested. Texaco and Tenneco announced some positive results in which gas in two wells and oil and gas in one well near the shelf break in Baltimore Canyon were encountered. It is not known at this time if these wells represent commercial discoveries. In addition, some of the data from the drilling in the Baltimore Canyon area indicate that deep water areas on the continental slope may be attractive for future oil and gas exploration (Edgar and Bayer, 1979).

On the shelf, the most promising frontier areas for future exploration that should be tested during the next 5 years are the Bering Sea, the Chuckchi Sea, and the Beaufort Sea surrounding northern Alaska. Current resource appraisals indicate that these areas may well contain in excess of 50 percent of the total oil assessed on the continental shelves in frontier areas of the United States. Thus, though the initial drilling results have been somewhat discouraging, new prospects have emerged, and many of the best areas still remain to be tested by drilling.

REFERENCES CITED

American Petroleum Institute, American Gas Association, and Canadian Petroleum Association, 1979, Reserves of crude oil, natural gas liquids and natural gas in the United States and Canada as of December 31, 1978, volume 33, 253 p. Edgar, N. Terence, and Bayer, Kenneth C., 1979, Assessing oil and gas resources on the U.S. Continental Margin: Oceanus, v. 22, no. 3, p. 13-22.

Miller, B. M., Thomsen, H. L., Dolton, G. L., Coury, A. B.,

Hendricks, T. A., Lennartz, F. E., Powers, R. B., Sable, E. G., and Barnes, K. L., 1975, Geological estimates of undiscovered recoverable oil and gas resources: U.S. Geological Survey Circular 725, 78 p.

Spurr, W. A., and Bonini, C. P., 1973, Statistical analysis for business decisions: Homewood, Illinois, Richard D. Irwin, Inc. p. 97-98, 114, 376, 378.

The definition of a map from the most recent edition of Webster's Dictionary, while not inaccurate, is hopelessly out of date. It is true that maps are usually "made on a flat surface" and show "the whole or part of an area" and "indicate the nature and relative position and size" of "cities, bodies of water, mountains, deserts" and "according to a chosen scale or projection."

However, a map is much more, especially today. Maps portray more than "selected features." Maps also record the way these same features change. As floods and landslides, bulldozers, and steam shovels work their will, a series of maps over time builds a dynamic picture of the effects of nature and man upon the face of the Earth.

However, there is a major revolution underway which is bringing about profound changes in the nature of maps and mapping. This revolution results from several forces, such as public policies relating to resources and the environment, technology, and rapid and far-reaching changes in the requirements of the users of maps. And it confronts the cartographic community in general, and the Geological Survey in particular, with serious technical and management challenges and enormous opportunities to be of service. The extent of the changes as well as the opportunities can perhaps be better appreciated in light of mapping tradition.

THE MAPPING TRADITION

Maps, and the cartographers who make them, have been with us throughout recorded history. Two thousand years ago, the Roman geographer Strabo proclaimed Homer to be the first geographer and Anaximander to be the first Greek to make maps, some six centuries before Strabo's own time.

Yet, in some respects, it might be said that maps predate even the written word. Primitive people made maps of the location of water, food, and shelter by scratching with pointed sticks on the ground. Mapping has evolved as much from a primal need to express spatially the location and size of the things of the Earth as it did from rational calculation.

The use of maps has also reflected man's age-old pursuit of power and wealth. Kings and generals long used maps and charts to guide their armies and navies to conquer and to rule their neighbors or to defend themselves and to show routes of commerce and communications and sources of wealth.

These interrelated needs of commerce, communication, and defense guided much of mapping's history in the United States. It is well known that George Washington, as a surveyor, traveled across the eastern mountains and into the valley of the Ohio. Less well known is the fact that, after his selection as Commander of the Continental Army, one of the first men he appointed was a geographer to prepare maps for the Continental Army. President Thomas Jefferson established an agency in the Treasury Department to chart coastal waterways and harbors because of their importance to the Nation's commerce and engaged Lewis and Clark to explore and chart the Louisiana Purchase.

This effort continued-and accelerated during the rest of the 19th century. With the impetus provided by the continued expansion of the frontier and the military and defense

needs of a growing Nation, the Federal Government, shortly after the Civil War, sent civilian scientific and engineering, and military expeditions into the West to assess natural resources and to find railroad and other transportation routes to the Pacific. Two of these expeditions were led by men who would become the first two Directors of the Geological Survey-Clarence King and John Wesley Powell. Both of these men brought back information in the form of maps, and, when the Geological Survey was established by Congress in 1879, it was only natural that a mapping program was an integral part of the new agency's activities.

The Geological Survey's mapping tradition, however, stemmed primarily from the resource interests of the Government and a desire for commercial exploitation of the Nation's vast treasures of land, water, and minerals. For much of the agency's century of service, deciding where to map and which maps to make has been related largely to the development of known resources and to the finding of new resources. It has been a distinctively utilitarian work. Indeed, when public policy demands began to change after World War II and led to the Survey's program to map the entire Nation in the standard 7.5-minute topographic series at 1:24,000 scale, there were some who complained that public funds were being spent for nothing more than surveying and mapping vast areas of uninhabited terrain. Yet uninhabited has never meant unimportant where things of the Earth are concerned; even the Antarctic Continent teaches much about the planet and the effects of people upon it.

The Geological Survey has endeavored to build toward complete cartographic coverage of the Nation, and this effort has been recognized through a series of directives giving the agency wide coordinating and leadership responsibilities for Federal mapping.

As it has from its inception, the Federal mapping program rests on three fundamental assumptions:

• Mapping the Nation is crucial to its economic development and environmental protection.

• Maps must contain many types of information built on a base of scientific validity and technical accuracy.

• Maps must communicate across a wide spectrum of customers and uses.

Accordingly, the National Mapping Program has evolved through a process of consultation with an everincreasing number of Federal and State agencies, representing the widest possible range of users and uses. As their needs for maps and cartographic information were assessed, some products were changed, new ones developed, and completely new services added.

The effort has considerably affected the Geological Survey's mapping products and services. In the 1950's and 1960's, the Geological Survey published one basic series

which was aimed at providing detailed national coverage-the 1:24,000-scale topographic quadrangle.

Extensive national map coverage is also available at other scales. More than one-half of the Nation is portrayed in maps at a scale of 1:100,000. The Nation is entirely covered in maps at a scale of 1:250,000. National coverage is also available at other smaller scales.

Perhaps more significant than the multiple scales of national coverage is the growth and expansion of subjects and themes treated by the maps themselves. Until the 1970's, maps by the Geological Survey dealt primarily with topographic mapping.

Today, the National Mapping Program publishes a variety of thematic and interpretive maps, from those showing energy sources, distribution, and uses to others that combine the topography of the land with the bathymetry (ocean floor contours) of

sea charts to provide a single

"family" of maps aimed at improving the capability to manage the Nation's coastal resources. The Survey also publishes a national series at the 1:2,500,000 scale showing land use and land cover.

What was for most of the Geological Survey's history primarily a topographic mapping service emerged in the 1970's as a comprehensive mapping organization with a full line of products and services, each developed and produced in response to specific public policies and national needs.

A TIME OF TRANSITION

The old truism "change begets change" appears to be at work in the Survey's mapping program, for it would seem that the establishment of the comprehensive National Mapping

Program has been less a culmination of this tradition than a prelude to still more innovations and program changes. What, in fact, confronts the Geological Survey is nothing less than a cartographic revolution that is fundamentally changing the nature of the National Mapping Program. The challenge of the next decade will be to manage this change in ways that strengthen the Geological Survey's cartographic services to public policy and to customer needs.

To understand the wide scope of the challenge, one might begin with public policy: the American people's views regarding the national treasures of land, water, and mineralsthe things that maps clarify, portray, and communicate.

If much of earlier public policy was devoted to resource development, it has now shifted to a greater emphasis on protection or conservation of natural resources. Environmental concerns, the effects of careless exploitation, and resource limits have

shaped a very different public policy emphasis.

Public officials at all levels of government are now called upon to balance conservation and development. For every consideration of resource development, there are many of resource conservation. And neither set of issues may be resolved independently of the other. It is a public policy that allows resource development but also demands its conservation, asking government to reclaim, to protect, to give back to the Earth in some measure what has been taken.

Two consequences of this public policy change have been an increase in the number of government agencies that depend on maps and an increase in the complexity of their requirements. It is a substantial change from the Geological Survey's older mapping tradition, which largely supported the advance of geological investigations in exploring and classifying the national domain to speed development of its resources. For a

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