01267cam a22002531 4500 gs 53000080 DLC 20260227111359.0 850718s1952 dcua f000 0 eng c gs 53000080 (OCoLC)12280026 U. S. Geol. Survey. Libr. TxHR DLC premarc QE75 .C5 no. 222 526.91 526.98* Geological Survey (U.S.) Twin low-oblique photography and the Twinplex plotter, prepared by the Topographic Division, Research and Technical Control Branch, Section of Photogrammetry. Washington, 1952. iii, 18 p. illus., diagrs. 27 cm. Geological Survey circular 222 "The text of this circular is an adaptation and combination of the following papers: 1. Hopkins, B. T., 1951, The Twinplex plotter for low-oblique photography. [Unpublished] 2. Radlinski, W. A., 1952, Convergent low-oblique photography and its application to the Twinplex: Photogrammetric engineering, v. 18, no. 3, pp. 596-597. 3. Thompson, M. M., 1950, the Twinplex, a new stereoplotting instrument; U. S. Geological Survey Circ. 82." Photographic surveying. Surveying Instruments. 28714 28714