Building a World Map using Layers in GIMP

[Hai-Etlik]

Is Inkscape it similar to TurboCAD and that ilk? I have used that for basic floor plans and blueprints.

There's a broadly similar basic concept. You are working with shapes as objects rather than a surface with colours applied to it. However Inkscape is a graphics editor, not a CAD tool; it is simply a graphics editor that works with shapes, rather than pixel surfaces. There are a lot of things CAD can do that it can't, and lots of things it can do that CAD can't.

Just as CAD tools are specialised for working with engineering data, there are similarly specialised tools for geographic data which are broadly called Geographic Information Systems or GIS. If you want, there are free GIS tools to play with but I'd suggest you consider it an advanced topic for later at best, and massive overkill to the point of being ridiculous at worst. I use them, but I'm already familiar with them.