Being an extensive ingress player, i'm quite surprised at this considering this should have been ingress code to begin with. Did pogo not share much code with ingress, just the dataset?
There was very little code shared on the backend. Ingress was appengine talking to custom clients via JSON, PGO was GCE/GKE talking to Unity clients via protobufs. Almost everything on the backend was written specifically for PGO because the Ingress codebase just couldn't scale, at least not cost-efficiently, to the number of users.
Also, Ingress is all about controlling areas of the map, while PGO was mostly based on points of interest, so the architecture needed to be quite different. I'll go into more detail when I post the writeup.
That's interesting! My friends who were avid Ingress players totally repeated the story that at least the geospatial data was somehow reused directly (to generate points of interest automatically based on places that figured into Ingress gameplay). It would be interesting to hear to what extent that was a misconception.
The POI is indeed reused from Ingress. For a very long time the only way to get a new POI in Pokémon GO is to make a new portal in Ingress and it will sync over.
