Projection Change at the
National Geographic Society

In 1998 the NGS decided to change from the Robinson (bottom of page) to the Winkel Tripel projection (above) on their World Reference Map. An internet site that discusses the change is:
http://www.nationalgeographic.com/features/2000/exploration/projections/

Background

The Winkel Tripel was the last of three projections developed by Oswald Winkel in 1921. John Parr Snyder refers to it as a modified Azimuthal, however, by using L. P. Lee's definitions [Lee_1944.pdf] the Tripel can also be classified as a Polyconic. It is neither conformal nor equal-area. On this projection the percentage of area distortion is less than the degrees of angular distortion. The Tripel is constructed by averaging the X then the Y outputs of the Aitoff and Equirectangular projection formulas. Winkel chose 50 degrees 28 minutes North & South as the standard parallels for the Equirectangular portion.

The formulas and paraphrased text (in Spanish) for the Winkel Tripel as presented on page 57 of "The World in Perspective" by Frank Canters and Hugo Decleir (1989) can be found at this Universitària Politècnica Barcelona site.

John Bartholomew [& Son, Ltd.] was the first to use the Winkel Tripel in an atlas: "The Times Atlas of the World - Mid-Century Edition" (5 volumes) 1955-60. Bartholomew still uses it for the major thematic maps and smaller inset maps in the "Times Atlas of the World - Comprehensive Edition" 1967-1997 and in various editions of the "Reader's Digest Great World Atlas" from 1961. The Bartholomew version uses 40 degrees North & South as the Equirectangular's standard parallels. The Bartholomew version superimposed over the NGS version.

Additional Resources

Also see:
Kessler, F.C., 2000, A Visual Basic Algorithm for the Winkel Tripel Projection: Cartography and Geographic Information Science, vol. 27, no. 2, pp. 177-183.

• English translation [newgrat.pdf], provided by of Germany.
  

• Original German text [winkel.pdf], from the Library of Congress.
  NOTE: This is a scan of a photocopied document and it may be less than useful! Graphics available in the English translation, above, are not included.

In addition to the above, has provided scans of later articles [in German] about the Winkel Tripel. They will appear here soon.

References

Bugayevskiy, L.M., and Snyder, J.P., 1995, Map projections - a reference manual: London, Taylor & Francis, 328 p. [An extensive revision in English of Bugayevskiy and Vakhrameyeva, 1992, Kartograficheskiye proyektsii.]
ISBN: 0-74840304-3

Snyder, J.P., and Voxland, P.M., 1989, An album of map projections: U.S. Geological Survey Prof. Paper 1453, 249 p. Reprinted 1994 with corrections. [Graticules for 90 projections, with brief descriptions and formulas.]

Snyder, J.P., 1993, Flattening the Earth - two thousand years of map projections: Chicago, University of Chicago Press. 365 p.
ISBN: 0-226-76747-7

Additional information:
Bartholomew Atlas information provided by Mike Ashworth, Senior Publishing Editor, World Atlases; Bartholomew & Son, Ltd. (Harper Collins Cartographic, UK)

Graphics:
The superimposed icosahedron, lines of equal "Angular Distortion", and lines of equal "Area Scale Factors" were produced with software developed by the late John Parr Snyder. Text was added with a paint program.

The color shaded relief map is courtesy of Daan Strebe. Mapthematics is where you can find Daan's Geocart map projection software for the Macintosh. He was also a consultant to the NGS on their change to the Winkel Tripel.

The black & white outline map with political boundaries was produced with "World". This DOS based program is capable of producing both raster and vector base maps in a large variety of different map projections.

The rest of the graphics were developed from software written by Paul Bryan Anderson. The small scale mapping database used, "MWDB-POLY", can be downloaded from the "MicroCAM for Windows" link at the bottom of this page.