(See pp. 777 and 793, July, 1927, Proceedings.)
Lieutenant Leonard Doughty, Jr., U. S. Navy.—A great deal of nonsense has been published recently on the subject of air mapping. The accounts of the Alaska survey in the newspapers and the Scientific American, and the present article by Lieutenant Boyden give the casual reader the impression that merely by taking a string of air pictures and pasting them together there is produced a map, “so exact as to satisfy the rigid requirements of civil engineers,” to quote Lieutenant Boyden’s article.
Unfortunately such is not the case. These patchwork affairs undoubtedly have their uses, and for many purposes may be adequate, even to a civil engineer. However, a degree of accuracy which might render a map suitable for planning a cow-path, for instance, might leave it practically useless for a water power project, or as an accurate survey or for directing artillery fire. In fact these mosaics cannot be called maps at all, in the engineering sense of the word.