Simple Polyconic and Rectangular Polyconic maps on scales of 1 : 1,000,000, 1 : 500,000, 1 : 250,000 and 1 : 125,000 of the topographical section of the General Staff, including all maps on these scales of British Africa. A rectilinear approximation to the simple polyconic is also used for the topographical sheets of the Survey of India. The simple polyconic is used for the 1 in. maps of the Militia Department of Canada.
Zenithal Projection by Balance of Errors (Airy’s).—The 10-mile to 1 in. Ordnance map of England.
Projection by Rectangular Spheroidal Co-ordinates.—The 1 : 2500 and the 6 in. Ordnance sheets of the United Kingdom, and the 1 in., 1⁄2 in. and 1⁄4 in. Ordnance maps of England. The cadastral plans of the Survey of India, and cadastral plans throughout the empire.
Authorities.—See Traité des projections des cartes géographiques, by A. Germain (Paris, 1865) and A Treatise on Projections, by T. Craig, United States Coast and Geodetic Survey (Washington, 1882). Both Germain and Craig (following Germain) make use of the term projections by development, a term which is apt to convey the impression that the spherical surface is developable. As this is not the case, and since such projections are conical, it is best to avoid the use of the term. For the history of the subject see d’Avezac, “Coup d’œil historique sur la projection des cartes géographiques,” Société de géographie de Paris (1863).
J. H. Lambert (Beiträge zum Gebrauch der Mathematik, u.s.w. Berlin, 1772) devised the following projections of the above list: 1, 15, 17, and 21; his transverse cylindrical orthomorphic and the transverse cylindrical equal-area have not been described, as they are seldom used. Among other contributors we mention Mercator, Euler, Gauss, C. B. Mollweide (1774-1825), Lagrange, Cassini, R. Bonne (1727-1795), Airy and Colonel A. R. Clarke.
(C. F. Cl.; A. R. C.)
[1] The ancient Greeks called a map Pinax, The Romans Tabula geographica. Mappa mundi was the medieval Latin for a map of the world which the ancients called Tabula totius orbis descriptionem continens.
[2] Close, “The Ideal Topographical Map,” Geog. Journal, vol. xxv. (1905).
[3] K. Peucker, Schattenplastik und Farbenplastik (Vienna, 1898); Geograph. Zeitschrift (1902 and 1908).