Date: Wed, 11 Jun 1997 15:46:15 +0200 (MET DST) From: "Martin J. Duerst" <firstname.lastname@example.org> To: Jeff de la Beaujardiere <email@example.com> cc: firstname.lastname@example.org, email@example.com Subject: Re: Map Colors (was: Re: New <AREA> syntax proposal) In-Reply-To: <199706111326.JAA00049@iniki.gsfc.nasa.gov> Message-ID: <Pine.SUN.3.96.970611154050.6897S-100000@enoshima> On Wed, 11 Jun 1997, Jeff de la Beaujardiere wrote: > Put another way, if you list the requirements for all possible maps, the > requirement is never greater than 4, so 4 is the maximum. Four is the magic number when each "territory" in the map is a single "blob". In many cases, this cannot be guaranteed. An example is political maps. As specific examlpes, there is a "blob" (a single vilage) of Germany completely surrounded by Switzerland. This wouldn't actually necessitate a new color, because Germany and Switzerland abound anyway. But states (Cantons) inside Switzerland are more complicated, and similar things will exist elsewhere. Regards, Martin.