The New Student's Reference Work/Triangulation

Trian′gula′tion, a branch of surveying and geodesy, in which the positions of points on the earth's surface are determined by measuring with great accuracy a baseline and then constructing triangles on this. By measuring the angles and knowing the base line, the other distances become a matter of trigonometrical calculation. In connection with the survey of the United States being made by the coast and geodetic survey, a series of such triangles extending across the country has been fixed with great accuracy. The exact shape of the earth is determined from such triangulation in connection with astronomical observations of latitude and longitude.