Adding SCNNode to GPS Coordinates

[ghost]

Hi, I am developing an ARKit application that takes a GPS coordinate, gets directions to the coordinate using Apple Maps, and overlays a SceneKit Sphere onto the AR space at every RouteStep of the directions. So basically every turn in the directions, I want to place a blue sphere at the location of the turn that I can see through the camera. I have a post on Stack Overflow here: https://stackoverflow.com/questions/49620583/adding-scnnode-to-gps-coordinates but I have not been able to figure this out. I just want a series of blue spheres leading me to my destination when I look through the camera.
Can you take a look at my detailed question and maybe see where I'm going wrong? Thanks!