Abstract
IN the method proposed in this paper, photographs are taken, with a surveying camera, at a pair of points, the plates being exposed in the vertical plane passing through both stations. A réseau, or a graduated back frame, gives the means of measuring the coordinates of any point on the plates with reference to the optical axis of the camera. After development and fixing, the negatives, or positives from them, are viewed in a stereoscopic measuring machine, which, by combining the pictures, renders possible the instant identification of any point common to the pair of plates. Movable micrometer wires traverse each field, and pointings may be made simultaneously with both eyes. The readings of the micrometers, referred to the réseau, give the three coordinates of the point by direct multiplication by, or division from, constants for the plates, which depend only on the focal length of the camera lens and the length of the base. When a sufficient number of points have been plotted from their coordinates, contour lines may be drawn. Theory of the Method.—Let A and B (Fig. 1) be the ends of the base and Q and Q′ the positions on the photographs of any point p.
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A Stereoscopic Method of Photographic Surveying 1 . Nature 66, 139–141 (1902). https://doi.org/10.1038/066139a0
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DOI: https://doi.org/10.1038/066139a0