[defrost]

> There is unambiguously one direction at Seattle (tangent to the Earth's surface)

and that tangent is the straight line, at least it is within the R^3 spatial universe I live within.

There's confusion here as the article presumes humans to be bound to an S^2 manifold and to consider a Great Circle to be a "straight line" which it certainly is not unless one lives within an S^2 Flatland.