Polygon rendering (For map better visualization)

I am developing something along the lines of Pokemon Go.

What I have done:

1. I am given spatial data which comes from OpenStreetMaps
2. My work so far looks like a GIS (Like google maps)

The road block:

3. The end goal is to view the map like how I would view a map from pokemon go.

I have to do the following:

• Given a 2D geometric primitive (Example a polygon defined by (x,y,z) points where z = 0)
  • Use 3D Rendering Pipeline to view the map from a 3D perspective.

Main Question

• What C++ libraries can I make use of to achieve all these "Pipelined sequence of operations" to give a 3D impression of my map?

Note: Didn't take computer graphics. Please use layman terms.