The topic, and the presenter, drew a large audience to learn more of the mysteries of map design. It appears that whilst there are notable and familiar projections on which to base maps, the options are without limit and decided by the cartographer according to the purpose of the map.

Keith took us through the choices between them, showing how detail from a spheroid is represented on a flat sheet through the geometry of a cylinder, cone or disc, in one of many variations, to achieve correctness in shape, direction, area, or scale – but not all at once.

“There was a wealth of fact information, carefully researched and attractively illustrated, so that the complexities of the subject became clearer and solutions easily appreciated.”

We learned to check a map’s projection details which set out what it can and cannot show reliably. It is not surprising that since a map can be trusted only within a design specification, it can present a slanted view of reality – let the reader beware. The classic misrepresentation of Mercator’s Greenland compared to Australia is a case in point. Another, illustrated in an equal-area world map, is the huge size of Brazil which tends to escape notice.

Keith’s talk contained entertaining asides, like the fact that the Prime Meridian has moved due to precession, 200 meters from the painted line at the Observatory which millions of visitors stand astride. He faced a barrage of sharp questions afterward and showed the depth of his scholarship in his answers.

Another great day for the Group and a deeper insight for its members into one of the most interesting aspects of cartography.

Photo credit: Kay Rees

By Les Isdale FMSIA

Map Group Presentation Wednesday 11 March 2026; article published in RGSQ Bulletin Vol 61 no 03 April 2026