Robert Hernandez10 said:One part of the solution is to use similar but distinct colors for groups that don't share much physical territory on a map—think Americans, Muslims, or Canadians. For instance, we could use dark red, red, and light red. Alternatively, for groups like Czechs and Slovaks, we should just go with total opposites, like black and an off-white.
The issue is that once maps get complicated, pretty much everyone ends up touching someone else. Take the US, for example. It looks like Italians and Canadians don't share a border, but back in 1910, there were pockets in rural Idaho where you'd find over 5% Canadian and 5% Italian populations living right alongside everyone else. Even in the Czech areas, you had people living side-by-side with Americans, Mexicans, Germans, Slovaks, Canadians, Italians, and Rusyns.