OpenStreetMap is built by a community of mappers that contribute and maintain data about roads, trails, cafés, railway stations, and much more, all over the world. This is a great open-source alternative to Google Maps.
Digitransit Platform is an open source journey planning solution that combines several open source components into a modern, highly available route planning service. Route planning algorithms and APIs are provided by Open Trip Planner (OTP). OTP is a great solution for general route planning but in order to provide top-notch journey planning other components such as Mobile friendly user interface, Map tile serving, Geocoding, and various data conversion tools are needed. Digitransit platform provides these tools.