UFO Sightings Map:
San Francisco Trajectories
This map shows the San Francisco Bay Area. About 25% of *U* UFO
reports indicate a final direction of travel. Here, those show as
red arrows. Other sightings are removed to reduce clutter.
Bayside demographics show clearly. Research for this database was done near one of those arrows. Arrows seem to indicate travel in all directions except towards the bay.
At this magnification, a map making trick shows. Apparent curves on wide area maps resolve to sections of straight lines. Map makers file lots of points for coastlines, borders, rivers etc.
Mapping algorithms simply connects the dots.