World Maps

The Cassini Projection§ is the transverse aspect of the Equidistant Cylindrical or Plate Carrée projection. It is instantly recognizable by the complex curves of its parallels, which are precisely circular at the poles in its spherical form, as shown here, becoming perfect squares at the equator. Although the projection is neither conformal nor equal area, it boasts a unique property: any point on the Earth may be chosen as the "pole" of the projection (here I chose 0ºN, 80ºW on the coast of Ecuador), and from that point the bearing and distance to all other points may be read directly as two rectangular coordinates. Introduced in 1745 by C. F. Cassini de Thury for the survey of France, the projection is still widely used in its more complex elliptical form, as elaborated by J. G. Soldner in the early 19th century. Older maps of this kind are still in print in Great Britain, and current ones in Cyprus, Czechoslovakia, Denmark, Germany, and Malaysia.

Projected inside AutoCAD® by Ptolemytm map projection software by W. Murray Sexton, from the Micro World Database, available from the Central Intelligence Agency.

§ John P. Snyder, Map Projections--A Working Manual, U.S. Geological Survey Professional Paper 1395, United States Government Printing Office, Washington D.C., 21987, pp. 92-95.

Cassini

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If you don’t have Whip! you can still see the JPGs, but to fully appreciate these engineering-quality maps, download and install the free Whip! viewer plug-in (3.5MB). You will then be able to see the scalable vector versions of select maps.

Click on the Vector Map link on each page to view the DWF file. You can pan around and zoom in on them, because they are true scaleable vector drawings. Using the Right Click menu, you can even turn layers on and off individually.

The extreme precision and detail of these maps cannot be reproduced in raster formats. The world maps are designed to be plotted at sizes up to 24” by 36” by robotic pen plotter. Some of the oil and gas maps were designed to be viewed up close when plotted at 300 dpi, at sizes up to 3 feet by 10 feet. The size of a BMP file of that scale would be approximately 1.5 gigabytes.

If you don’t have Whip! you can still see the JPGs, but to fully appreciate these engineering-quality maps, download and install the free Whip! viewer plug-in (3.5MB). You will then be able to see the scalable vector versions of select maps.

Click on the Vector Map link on each page to view the DWF file. You can pan around and zoom in on them, because they are true scaleable vector drawings. Using the Right Click menu, you can even turn layers on and off individually.

If you have limited bandwidth, be aware that the DWF files contained in this site range from about 100KB to about 750KB.