Geographical accuracy versus inaccurate representation

We all have been taught geography in school and shown maps of the world. But, back in 1977, a man named Peters grabbed a map from an 1855 English clergyman, named Gall, and peddled it as his own map. Worse, he peddled it as a more “socially” and “geographically” accurate portrayal of the Earth than the previous “biased” Mercator map that dates from the 1500s. Actually, he was quite wrong and quite right. Sadly, the two maps continue to be a bone of contention, particularly in university circles. The problem is that the two maps have vastly different purposes. Each is accurate, provided you know the purpose of the map.

Mercator devised his map from the view of the sailor, who must navigate from one place to another, and arrive there as accurately as possible. Thus, the Mercator Projection allows a sailor to easily calculate direction using a compass. You can lay a Mercator Projection map on a table and put a compass on top of it. If you are in the west of England and wish to sail to a port in the east of the USA, you can draw a straight line between your port in England and the port in the USA and take a compass bearing on the flat map. You can follow that same compass bearing on the sea, and, provided currents and wind do not push you aside, you will reach your destination. If there are intervening land masses, the navigation becomes a little more complicated, but it works. But, the Mercator Projection has a major problem. In order to allow sailors to navigate correctly, the projection strongly distorts the relative size of different countries.

Gall (and Peters) devised his map from the viewpoint of relative sizes of different countries. You cannot use his map for sailing. However, you can use his map to compare the relative sizes of countries. Almost no one in the world realizes the relative sizes of countries. Africa is the largest continent in the world. [Note: I have now been corrected. Asia is the largest continent, see comments.] Over two USAs can fit into Africa. Close to two USAs can fit into South America. The number of Europe’s that can fit into Africa is truly amazing. Greenland is significantly smaller than a Mercator Projection shows. There are various other comparisons that could be made.

In one sense Gall is correct. In another sense Mercator is correct. Gall is correct in that the Mercator Projection gives a “false” impression of the relative size of countries. However, Peters is wrong in that there was no intention by Mercator to have an Euro-centric map. Rather Mercator’s purpose was to produce a map that could be easily used by sailors. In that, he was a full success. However, in order to accomplish that end, he distorted the relative size of countries.

Gall’s purpose was to show the relative size of countries. However, in order to accomplish that end, he made his map useless to sailors. He did not “correct” earlier maps. Rather, his map is useless to sailors.

Neither each map is fully correct. The only correct map is when you buy a 3D map (a sphere) of the world on a stand. However, that type of map is not helpful for sailing and cannot be readily portrayed on a 2D (flat) piece of paper.

OK, so what do I recommend? Use both maps! If you want to navigate, use the Mercator Projection. If you want to see relative sized, use the Gall/Peters map. I also recommend that you avoid the silly (and misleading) argument that one or the other of the maps is better.