Como referencia sobre el tema de mapear patios traseros (backyars) te comparto las guidelines de la wiki: https://wiki.openstreetmap.org/wiki/Mapping_private_information

cito:
- Limit the detail of mapping private backyards. As a guideline, permanently installed private swimming pools (add access=private as appropriate) or some structures in semi-public gardens are acceptable. More detailed information is likely to be not acceptable or borderline.

- Mapping private buildings, private roads (including driveways), and private parking is completely acceptable. Add access=private as appropriate to roads, parking lots, etc. However, annoying artifacts may appear in applications like Pokémon Go with short driveways.