Édouard-Gaston Daniel Deville (February 21, 1849 in La Charité, France – September 21, 1924 in Ottawa, Ontario, Canada) was the first to perfect a practical method of photogrammetry, the making of maps based on photography. He was the Surveyor General of Canada (1885–1924) and Canada's Director General for the Bureau of Surveys (1922–24). During his lifetime, Canadian surveyors had used his phototopography to map 83,678 square kilometres, roughly the size of the United Kingdom.
Before Deville moved to Canada in 1874, he had attended naval school, served in the French navy (reaching the rank of Captain) and had conducted hydrographic surveys in the South Sea islands and Peru.
In 1875, Deville began working as a surveyor and astronomer in Quebec, Canada. He was quickly promoted to the position of the province's top surveyor, Inspector of Surveys. He passed exams in high-level survey theory, earning the rare designation of Dominion Topographic Surveyor. In 1880, he joined the survey for homesteads in the Prairie provinces with the Department of the Interior in Ottawa. For many years, Deville directed Canadian surveying activities. He used innovative techniques to deal with the challenges of surveying in Canada, including a special method of mapping mountainous regions that he invented.
In 1881, Deville was appointed inspector for Dominion Land Surveys. In 1885, he became Surveyor General of Canada.
In 1922, he represented Canada at a geophysics conference in Rome, and his expertise on mountain surveys became sought after internationally. A copy of his camera was used to map the north slope of Mount Everest. His technology was adopted by the Geological Survey of Canada and the International Boundary Commission.
To meet these challenges of surveying in the Rocky Mountains Deville experimented with mapping methods developed by French army engineer Aimé Laussedat. Deville used Laussedat's principle of elevated photography, and refined a technique of creating large-scale maps from these photographs. This required him to design a rugged, lightweight field camera that could be carried long distances.