Abstract
THE progress made of late years in topographical surveying by means of aerial photography is strikingly illustrated by a recent report from the Canadian Department of the Interior. The Dominion of Canada with its vast expanse of hyperborean territory, the accessibility of which is rendered extremely difficult by the physical conditions, has proved a splendid field for this modern method of planimetry. Within the last decade, a total area of 402,500 sq. miles has been covered by aerial photography, comprising 125,000 sq. miles by vertical photographs and 277,500 sq. miles by oblique photographs. Vertical photographs are serviceable for mapping to fairly large scales, or in districts where the country is rough and mountainous, while oblique photographs are more particularly adapted to the exploratory mapping of extensive areas of forest and lakeland of fairly uniform level, such as constitute so large a proportion of northern Canada. Indeed, the oblique method is known as the Canadian method and has been adopted in other countries where the conditions are similar. Its moderate cost, flexibility and the small amount of ground surveying required render it particularly applicable to northern latitudes. During the last ten years, forty map sheets on a scale of four miles to the inch, each covering an area of 5,000-6,500 sq. miles, and three map sheets on a scale of eight miles to the inch, each covering an area roughly four times as great as the 4 mile-inch maps, have been compiled from oblique photographs and published in a National Topographic Series designed to cover eventually the entire area of Canada. Other map sheets have been issued which have been compiled from vertical photographs on larger scales of 1 or 2 miles to the inch.
Article PDF
Rights and permissions
About this article
Cite this article
Aerial Photography in Map-making. Nature 130, 538 (1932). https://doi.org/10.1038/130538c0
Issue Date:
DOI: https://doi.org/10.1038/130538c0