Page images
[merged small][merged small][merged small][graphic][subsumed][subsumed][subsumed][ocr errors][ocr errors][graphic]

topographic or planimetric county maps, and l:100,000-scale topographic or planimetric quadrangle maps. More than 150 topographicbathymetric maps have been published for coastal area planning. Land use and land cover maps are complete for 2.5 million square miles and are available in the l:250,00O-scale or, in selected areas, in the l:100,000-scale quadrangle format.

• Digital cartography, including the

production of base categories of cartographic data at standard scales, accuracies, and formats suitable for computer-based analysis. The Geological Survey chairs a Department of the Interior committee to coordinate digital cartography activities within the Department. Additionally, the Office of Management and Budget issued a memorandum to foster better coordination of digital cartography activities in all Federal agencies. The Geological Survey has been delegated the lead role in this activity and chairs the Federal Interagency Coordinating Committee on Digital Cartography.

• Information and data services,

including the acquisition and dissemination of information about U.S. maps, charts, aerial and space photographs and images, geodetic control, cartographic and geographic digital data, and other related information; distribution of earth science information to the public; and sale of maps and maprelated products directly and through over 3,300 commercial dealers.

• Advanced development and

engineering to improve the quality of standard products; to provide new products, such as digital cartographic data, that make maps and map-related information more useful to users; to reduce costs and to increase productivity of mapping activities; to acquire innovative and more useful equipment; and to design and develop techniques and

systems to advance the mapping of high-priority areas of the country.

• Cartographic and geographic

research with particular emphasis on spatial data techniques for studies using modern geographic analysis with new and improved cartographic concepts and techniques.

• International activities, including the

coordination of the Division's participation in international cartographic, geographic, surveying, remote sensing, and other maprelated activities.


For fiscal year 1984, National Mapping Division funding totaled about $110 million. Funding sources included direct congressional appropriations, funds transferred from other Federal agencies, joint funding agreements through the Federal-State Cooperative Program, funds transferred from local agencies, and funds received from the sale of published maps.

The permanent full-time personnel strength of the Division at the end of fiscal year 1984 was 1,904, representing a work force skilled in cartography, geography, computer science, engineering, physical science, photographic and remote sensing technology, and information sciences.


In the following sections, highlights from some of the major activities are described.

Provisional Maps

In 1982, the Geological Survey initiated a series of provisional edition topographic maps to expedite completion of the 8,500 7.5-minute quadrangle areas not covered by l:24,000-scale mapping. Under this accelerated mapping program, almost all of the unmapped areas are targeted for provisional mapping, which will allow completion of 7.5-minute map coverage of the conterminous United States in

fiscal year 1989. Provisional maps of unmapped 15-minute quadrangle areas in Alaska also will be produced allowing l:63,360-scale map coverage of Alaska to be completed concurrently with the

l:24,000-scale coverage of the conterminous United States.

Provisional maps are prepared to the same map accuracy standards and contain essentially the same level of content as standard topographic maps but reflect a provisional rather than a finished map appearance. They are printed in four or five colors and are made available through standard distribution procedures. The maps can be produced manually or with automated techniques. The first maps in the provisional series were produced manually using standard compilation techniques, with some linework and lettering done by hand.

Computer technology is the basis for the automated processing of provisional maps. Maps are produced in the following stages: (1) information collection: aerial photographs are used in plotting equipment to record information from the photographs on computer tapes, (2) information editing: appropriate map symbols are applied to represent properly the features on the map, and errors and deficiencies are corrected, and (3) cartographic plotting: newly developed computer programs produce and position certain descriptive lettering, contour labels, and control elevations on the maps. These automated processes further shorten the map production cycle for provisional maps and place the product in the hands of the user at an earlier date.

After completion of the provisional mapping program, the provisional maps will be republished as standard editions in conjunction with the revision of these maps.

Digital Cartography

Map data in digital form are being applied to an increasing number of complex problems. Applications are not limited to the earth sciences but address many diverse and complex problems. An important factor in the growth of digital cartographic data applications is the development of geographic information

systems. These systems have the capability to compare rapidly and sort through large amounts of digital data on multiple topics about the land and its resources. Maps depicting the results of

the analysis can be prepared quickly and more accurately using automated procedures.

To meet the demand for standardized digital cartographic data, the Geological Survey is digitizing base categories of cartographic information from its topographic maps and making these data available from the National Digital Cartographic Data Base. The digitized data, available in two forms, are digital line graphs and digital elevation models (fig. 3). The digital line graphs are digital data files consisting of planimetric (line map) information. Currently, the following four categories of digital line graphs are being collected from l:24,00O-scale maps: the public land net, boundaries, hydrography, and transportation. The digital elevation models are digitized elevations shown at 30-meter intervals horizontally throughout a quadrangle. Hydrography and transportation features also are being digitized from l:100,000-scale maps. Boundary, hydrography, and transportation features from the l:2,000,000-scale sectional maps of the National Atlas of the United States of America are available in digital form for the entire United States. The data base also includes elevation data from the l:250,000-scale map series, land use and land cover data, and geographic names data.

In a related area of activity, the coordination of Federal digital cartographic: data programs, the Geological Survey expanded its coordination activities within the Department of the Interior by chairing the Interior Digital Cartography Coordination Committee. Also, the Geological Survey was delegated the load role in implementing the Office of

Management and Budget objective of fostering better coordination of all Federal digital cartography programs. In that role, the Geological Survey chairs the Federal Interagency Coordinating Committee on Digital Cartography. The Geological Survey continues to identify and respond to

[merged small][graphic][merged small][merged small]

valuable mapping tools, map supplements, and as alternatives to standard maps. As a result, it responds to these needs through the image mapping program.

Image mapping in the form of orthophotoquads provides relatively low-cost products that can be prepared in about one-third of the time required for line maps. For areas of the conterminous United States unmapped at the l:24,000 scale, black-and-white orthophotoquads serve as interim maps until new 7.5-minute topographic maps become available. For areas with 7.5-minute map coverage, orthophotoquads serve as map supplements. Orthophotoquads have been prepared for about 57 percent of the conterminous United States. During fiscal year 1984. the Geological Survey prepared about 1,900 orthophotoquads.

In Alaska, 15-minute orthophotoquads are being prepared at the l:63,360 scale in cooperation with the Bureau of Land Management and the State of Alaska. In fiscal year 1984,140 quadrangles were produced. Coverage of most portions of the State is anticipated over the next decade.

Responding to requirements of the U.S. Customs Service and the International Boundary and Water Commission, the Geological Survey is preparing maps of the international boundary between the United States and Mexico. Currently, 48 of the projected 201 photoimage maps in simulated natural color at l:25,000 scale have been published.

The Geological Survey has been experimenting with Landsat imagery to assess its utility in the production of image maps which can be used in a variety of earth science applications. Landsat image mapping products which have been completed are the experimental Las Vegas Landsat 3 multispectral scanner l:250,000-scale image map (as shown on the Yearbook cover), the Dyersburg, Tcnnessoe-MissouriKentucky-Arkansasl:100,000-scale image map, and the Washington, D.C., and Vicinity Landsat 4 Thematic Mapper l:100,000-scale image map. The National Mapping Division will prepare about 25 Landsat image products annually in fiscal years 1985 and 1986 to meet emerging requirements.

On July 2,1984, the Great Salt Lake, Utah, crested at a peak elevation of 4209.25 feet above mean sea level, the highest lake elevation since July 1,1878. This recent high lake level was recorded successfully on Landsat imagery acquired on June 25, on July 2, and on July 11. During August and September 1984, the National Mapping Division, in cooperation with the Water Resources Division, prepared a Landsat image map of the Great Salt Lake and vicinity at l:125,000 scale from Thematic Mapper data. The four-color image map is printed on the reverse side of the 1974 Great Salt Lake and Vicinity topographic map. In addition to the high lake level, the image map shows the major cultural changes that have taken place within the past 10 years. This project demonstrated that a transitory phenomenon, such as the unusual rise of the Great Salt Lake, can be mapped within a relatively short period of time. With the use of space imagery and the computer processing of digital data, the time required for such mapping can be reduced from the several years of a normal mapping project to a few weeks.

The Geological Survey continues to evaluate side-looking airborne radar imagery for use in geoscience mapping. Twelve controlled l:250.000-scale quadrangle image mosaics of the Aleutian Islands in Alaska have been printed by screenless lithography and are available with or without updated topographic maps on the reverse side. Thirty-eight l:250,000-scale radar image mosaics of the Appalachian region from Alabama to Maine are being compiled from data acquired in 1984.

Information Services

The Geological Survey disseminates much of the Nation's earth science information through its Public Inquiries Offices, National Cartographic Information Center offices, and Earth Resources Observation Systems Data Center. The National Mapping Division operates these public access points for the Survey and sells the Survey's books, maps, map-related products, aerial photographs, and digitized cartographic and earth science data on tapes. Survey maps also are sold through a network of

« PreviousContinue »