Mapping the real world into OpenGL coordinates

Hello, now i develop for android in open gl es 2.0.
My plan is showing a parallel map of the world on the smartphone screen.
The LookAt Center will set by the GPS Location.
If the user moving, parts of the map will be removed and another will be created.
The maximal values for centerX and centerY will be 1300000.f
Im not sure if this the best solution.
Or is manuell handling (Working mit Offsets etc.) better than.

Sorry for my bad english. I hope you unterstand me.

Thank you.