[f. L. triangul-um + -ATE3, or f. ppl. stem of med.L. *triangulāre: cf. also F. trianguler.]
1. trans. Surveying (also transf., as in Astron.). To measure and map out (a region or territory) by tracing a series or network of triangles from a baseline and measuring their sides and angles; to determine (e.g., a distance or altitude) in this way. Also absol.
1833. Herschel, Astron., iv. 157. We may, as upon the earth, triangulate, by measuring … their [the stars’] angular distances from each other.
1855. F. Galton, in Cambr. Ess., 93. A running survey of a new country is best made by triangulating as much as is practicable.
1891. Cent. Dict., s.v., To triangulate the height of a mountain.
fig. 1860. O. W. Holmes, Elsie V., xix. A sagacious person,… who has triangulated a race, that is taken three or more observations from the several standing-places of three different generations.
b. gen. or allusively. To mark out into triangles.
1853. Kane, Grinnell Exp., xxvi. (1856), 212. The entire plain is triangulated with ice-barricades.
1879. J. Timbs, in Cassell’s Techn. Educ., IV. 343/2. The system of wires … stretching across the sky-line of great thoroughfares, and visibly triangulating the metropolis in every direction.
2. To divide or convert into triangles.
1864. Webster, Triangulate … 2. To make triangular.
1901. C. W. Brown, in Cycl. Tour, Cl. Gaz., July, 298/2. A plan which completely triangulates the four-sided figure of the frame and converts it into two distinct triangles.
Hence Triangulating vbl. sb. and ppl. a.
1861. Wilson & Geikie, Mem. E. Forbes, x. 280. He was ready and eager to avail himself of a triangulating cruise with Lieutenant Spratt. Ibid., 290. Messrs. Spratt and Forbes proceeded to make the triangulating observations.
