Abstract
THE annual report of the Director of the United States Coast and Geodetic Survey for the year 1930–31 (Washington, 1931, 45 pp., 60 cents) describes briefly the wide range and large extent of the activities of this important and progressive organisation. It has as a frontispiece a photograph of the new surveying vessel (one of several possessed by the Survey) Hydrographer, commissioned in March 1931, and fully equipped with sound-ranging apparatus for depth-surveys sound-ranging is also used for locating the position of the ship from the shore at the time of each depth-measurement. The use of these methods has greatly increased the rapidity of the coastal survey work. The control survey work on land has also been rendered much more rapid and less expensive by abandoning the erection of the large wooden towers formerly used in flat or rolling country, at points about ten miles apart, to enable the observers to see across such distances over intervening trees and other obstructions. These towers were often 100 feet or more in height, each being double, so that the observer could walk on the outer platform, unconnected with the inner tower carrying the instrument. They contained large quantities of material, used once only, and required much time to erect. They are now replaced by portable steel towers, which can be erected by five men in less than a single working day, and used many times, their transport from one place to another being made by trailer trucks. An improved and smaller theodolite has also been devised and brought into use.
Article PDF
Rights and permissions
About this article
Cite this article
Geodetic Surveying in the United States. Nature 130, 271 (1932). https://doi.org/10.1038/130271c0
Issue Date:
DOI: https://doi.org/10.1038/130271c0