MAPPING AND CHARTING FROM THE AIR (FIGS. 54 TO 82) Mention has already been made (p. 56) of the experiment in map-making carried out by the Army Air Service and the United States Geological Survey at Schoolcraft, Mich. The results of that experiment and of others of the sort are sufficient to establish the fact that the air camera is destined to become a valuable addition to the map-maker’s equipment. The extent to which it will be used depends, of course, upon the degree to which its present imperfections are corrected and its possibilities developed. The Board of Surveys and Maps of the United States government has recently published the results of its study of air photography for use in map-making.[6] [Illustration: FIG. 54--View across the western end of Lake Erie, looking in a northeasterly direction (see Fig. 55). Oblique photograph taken from 18,000 feet above Port Clinton, Ohio, by Lieut. G. W. Goddard, showing, in the foreground at the right, Catawba “Island,” a part of the mainland, and, at the left, Put-in-Bay and the islands around it. In the distance below the white clouds are a small island (Middle Island) and a large one (Pelee Island). In the upper left-hand corner is seen Point Pelee and the Canadian shore to the northeast of it about 30 miles away. At Put-in-Bay was fought, September 10, 1813, the Battle of Lake Erie, in which Commodore Perry defeated the British. The monument commemorating this victory can be distinguished in the photograph as a white shaft. Although most vertical airplane photographs are in the nature of large-scale maps, this view illustrates how a large area can be covered in an oblique view taken at a high altitude--an area, when transformed, of appreciable size even on a small-scale map, such as, for example, Fig. 55.] [Illustration: FIG. 55--Map of the western end of Lake Erie showing the area covered within the angle of vision of Fig. 54. Scale, 1:1,400,000. FIGS. 54 (upper) and 55 (lower). For explanation, see bottom of opposite page.] SCALE AND HORIZONTAL CONTROL OF VERTICAL PHOTOGRAPHS