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| Venice | Ingle-wood | South Gate | Whittier |
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| San Pedro | Seal Beach |
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| Scale | 1:62,500 |
| Contours | 50 feet |
| Polyconic projection. To place on North
American datum move projection lines 640 feet south and 460 feet west. |
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| Scale | 1:125,000 |
| Contours | 100 feet |
| Polyconic projection. To place on North
American datum move projection lines 600 feet south and 500 feet west. |
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| Readjustment indicates that elevations on this map should be increased 1 foot. | |
The Corona Quad has the following statement on the back:
"THE TOPOGRAPHIC MAPS OF THE UNITED STATES
The United States Geological Survey is making a series of standard topographic maps to cover the United States. This work has been in progress since 1882, and the published maps cover more than 47% of the country, exclusive of outlying possessions.
The maps are published on sheets that measure about 16 1/2 by 20 inches. Under the general plan adopted the country is divided into quadrangles bounded by parallels of latitude and meridians of longitude. These quadrangles are mapped on different scales, the scale selected for each map being that which is best adapted to general use in the development of the country, and consequently, though the standard maps are of nearly uniform size, the areas that they represent are of different sizes. On the lower margin of each map are printed graphic scales showing distances in feet, meters, miles, and kilometers. In addition, the scale of the map is shown by a fraction expressing a fixed ratio between linear measurements on the map and corresponding distances on the ground. For example, the scale 1/62,500 means that one unit on the map (such as 1 inch, 1 foot, or 1 meter) represents 62,500 of the same units on the earth's surface.
Although some areas are surveyed and some maps are compiled and published on special scales for special purposes, the standard topographic surveys and the resulting maps have for many years been of three types, differentiated as follows:
1. Surveys of areas in which there are problems of great public importance--relating, for example, to mineral development, irrigation, or reclamation of swamp areas--are made with sufficient detail to be used in the publication of maps on a scale of 1/31,680 (1 inch=one-half mile) or 1/24,000 (1 inch=2,000 feet), with a contour interval of 1 to 100 feet, according to the relief of the particular area mapped.
2. Surveys of areas in which there are problems of average public importance, such as most of the basin of the Mississippi and its tributaries, are made with sufficient detail to be used in the publication of maps on a scale of 1/62,500 (1 inch=nearly 1 mile), with a contour interval of 10 to 100 feet.
3. Surveys of areas in which the problems are of minor public importance, such as much of the mountain or desert region of Arizona or New Mexico, and the high mountain area of the northwest, are made with sufficient detail to be used in the publication of maps on a scale of 1/125,000 (1 inch=nearly 2 miles) or 1/250,000 (1 inch=nearly 4 miles), with a contour interval of 20 to 250 feet.
The aerial camera is now being used in mapping. From the information recorded on the photographs, planimetric maps, which show only drainage and culture, have been made for some areas of the United States. By the use of stereoscopic plotting apparatus, aerial photographs are utilized also in the making of the regular topographic maps, which show relief as well as drainage and culture.
A topographic survey of Alaska has been in progress since 1898, and nearly 44 percent of its area has now been mapped. About 15 percent of the Territory has been covered by maps on a scale of 1/500,000 (1 inch=nearly 8 miles). For most of the remainder of the area surveyed the maps published are on a scale of 1/250,000 (1 inch=nearly 4 miles). For some areas of particular economic importance, covering about 4,300 square miles, the maps published are on a scale of 1/62,500 (1 inch=nearly 1 mile) or larger. In addition to the area covered by topographic maps, about 11,300 square miles of southeastern Alaska has been covered by planimetric maps on scales of 1/125,000 and 1/250,000.
The Hawaiian Islands have been surveyed, and the resulting maps are published on a scale of 1/62,500.
A survey of Puerto Rico is now in progress. The scale of the published maps is 1/30,000.
The features shown on..." (it goes on to describe the features shown on the maps).
"The contour interval..." (it goes on to describe the contour interval).
"Lettering and the works of man..." (it goes on to describe those).
"Geologic maps of some of the areas shown ..." (it goes on to describe the folios of these).
"Index maps of each State and of Alaska and Hawaii showing the areas covered by topographic maps and geologic folios published by the United States Geological Survey may be obtained free. Copies of the standard topographic maps may be obtained for 10 cents each; some special maps are sold at different prices. A discount of 40 percent is allowed on an order amounting to $5 or more at the retail price. The discount is allowed on an order for maps alone, either of one kind or in any assortment, or for maps together with geologic folios. The geologic folios are sold for 25 cents or more each, the price depending on the size of the folio. A circular describing the folios will be sent on request.
Applications for maps or folios should be accompanied by cash, draft, or money order (not postage stamps) and should be addressed to
THE DIRECTOR
United States Geological Survey,
Washington, D. C.
November 1937"
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Copyright © 1998-2008
Gregory J. Reis
