NavList:

And if you think about it, every "Mercator chart" you have ever seen is actually an "approximation" of a Mercator chart unless the printing program did an infinite number of calculations and unless the printer can print to the level of precision of sub-atomic particles. The table of Meridional parts in Bowditch are in one minute increments and only to one decimal point precision so this "approximates" the true Mercator chart into only 5400 increments that cover "approximately" ten million meters. The original table of Meridional parts that was published by Edward Wright in 1599 was even less precise.

So I am one who advocates "good enough" and this is what practical navigators have been doing for centuries.

gl