Japan 19-plane rectangular coordinates ↔ lat/lon (approx).
Approx. Japan plane rectangular (systems 1–19) ↔ lat/lon (GRS80 Gauss–Krüger).
System: 9 X (N): -35363.238 m Y (E): -5992.920 m
Yes.
No.
DMS ↔ decimal degrees (lat/lon).
Haversine km/mi + bearing.
Convert GPX track points ↔ GeoJSON LineString.
Japan zip → address.