I just started GMing a game, and this was the mapping solution we came up with:
https://drive.google.com/open?id=1FmFr6 ... sp=sharing
This is a shared MyMaps Google map with notes from the very first session. The players have access to it and will add information as the game goes on.
Since we all live in this same Brooklyn neighborhood, we're treating "sectors" as something more like "neighborhoods and landmarks", and building encounters off of that.
Will report back as to how it's going, but so far, so good!