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Me before I learned how to use JOSM
(lemmy.ca)
Overview:
Discussion on the Openstreetmap service that has the most open map data that began in 2004.
Apps:
JOSM: Map editor
Comaps: Offline maps that's great for walking/hiking/cycling
Magic Earth: Great for driving
Related:
The hallways and stairs in my school are mapped. Heck, a demolished building was updated in OSM faster than the map on the school's website