Hello,
I do beg every body's forgiveness as I struggle to understand the dynamics of programming and how best to express my vision and goals.
To start, a game that I enjoy playing is a 2D game of course played on a square surface. If you start at point a and move in a straight line to the right when you come to the edge you can go no further. Now in my mind you should be repositioned to the the left side and be able to continue on your path.
It is my impression that the only why to accomplish this goal is to have a spherical game space...of course I could be wrong.
As a beginning base for my project I would prefer this MyWorld.jpgas a game space. With the ability to zoom into street level yet not have the streets or buildings one would find in say google maps. Natural Earth does have the appropriate dataset although there would need to be some work done as when their maps are zoomed in they get blurry. But, I am sure there is a height map, shapefile that can resolve that issue.
Then there is the issue of the actual ...algorithm... to create the proper paths such as something like these.MyWorldBasicTravelLines.jpg

Now, not being a programmer much less a game programmer, I can image that there is some process to achieve this goal. But, I am not yet knowledgeable enough to understand it.

I, in my project am attempting to fly from space, land, drive in a vehicle until I come to the ocean, then board a ship etc. etc.
Once I figure out the 3D terrain then I hope I can then combine it with other open source code snippets to finish the project...easier said then done.

So, I guess the real question is. Does a terrain engine or a game engine allow for this type of path following? Will I need a PhD in mathematics to program the behavior or has some wizard already figured it out? If there is an engine that will allow embedding satellite imaging to create a natural earth terrain could some one suggest it to me?

As always all advice an d admonishments are appreciated.
Bill