Numerous scientific uses for aerial views seem likely. Prominent among these is their use in geology, for the study of the various forms of earth sculpture. Pictures from the air of extinct volcanoes will give information as to their configuration that would otherwise require months of painstaking survey to obtain. Aerial photographs of active volcanoes (Fig. 198), showing the results of a succession of outbursts—one obliterating the other—would prove of the greatest value, especially when studied in conjunction with other scientific data, the whole making a record unobtainable by any other means. In earthquake regions—notably Southern Italy and Japan—the changing coast lines, shallows and safe harbors, could be promptly ascertained after the subsidence of each fresh shock, with a consequent keeping open of trade routes and often the saving of life. River courses, glacier formations, cañons, and all the larger natural formations which man usually sees only in minute sections, and which he must build up in his mind's eye or by models, are today quickly and accurately recorded by the camera in the air. Such formations as coral reefs, whose configurations can now be accurately learned only by laborious surveys of a limited number, could be studied in quantity and with heretofore unknown satisfaction as the result of a single expedition with a ship-carrying seaplane and aerial camera. Another scientific field—probably one of many similar ones—lies in the study of the waves set up by ships (Fig. 199). These are of extreme importance in the realm of naval architecture, but before the day of the airplane could never be easily studied in full scale. CHAPTER XXXIII EXPLORATION AND MAPPING Aerial photographic mapping in war-time has been almost entirely confined to inserting new details in old maps. For such work some distortion or a lack of complete information on altitude and directions is not a serious matter, because the known permanent outlines serve as a basis. Furthermore, in so far as outline maps are concerned, as distinguished from pictorial maps, these have been drawn on the ordinary scales, and with the ordinary conventions of engineering map practice. Aerial photography may be used in the future in practically the same way, as an aid to the quick recording of those minute details which would ordinarily consume an enormous amount of labor to survey directly. The region shown in Fig. 200 affords a good illustration. A discouraging amount of time and effort would be required to map this section of Virginia by the usual methods, while the smallest curve of creek and shore is instantly and completely recorded on a single photographic plate. But there are other possibilities, diverging from this application both toward greater and lesser requirements for precision.