This style is called isometric. It is commonly used for computer gaming and pixelart.
The easiest way to create such a "map" (image?) is to start with the propper isometric grid and then use isometric clip-art (of which there is a fairly large amount on the net, mainly due to the proliferation of sim-xxx games that used such art).
The hard way to do it is to draw it all from scratch, in the isometric view.
A somewhat middle of the road approach is to make it in a 3d modeling program and render it using isometric perspective.
Hope that helps.
Thank you very much, I'm searching it right now, that did help a lot and I think it's enough to get me started. Once again, thank you