LunarMongoose
King
In addition to a globe view overlay, couldn't it be displayed in the tile hover text like the latitude/longitude? If ocean currents could be done as well, then couldn't they both be tile hover text (as well as globe view overlay)? Think of the movement modifier you'd get if you had both the ocean current and the trade winds going in your favor or both going against you.
A new type of map view overlay is not possible to implement as far as I know. Hover text on individual tiles would be a disaster as a gameplay mechanic, since you would have no way of evaluating the best overall path to take, and with each movement point on each turn you'd be forced to stop and look at 3 different tiles, at least, to see which is best. It'd be tedious and annoying. Also, programming the AI to pathfind through such a maze would be pretty easy, but it would add a lot of computation time to the turnovers which can already get pretty slow, for an unnecessary "fluff" type system.
*However* I've recently discovered in my work for Civ5 that my geostrophic climate generator my be broken on this map, so you may occasionally get weird results by turning that up. I'm using a much better system for diagnosing map data with colored bitmaps this time (in PW2 it was text based kinda like ascii art.) and it's uncovering alot of rough edges in my old way of calculating things.
Ceph, there are those of us who would be enormously grateful should an update of this sort for the Civ4 version be forthcoming in the future... Hopefully we can reverse-engineer it from your Civ5 version though if we have to, heh.