interpolate

Where fraction of the way from fromLocation to toLocation is, or null when this spatial model cannot say.

Null is a supported answer and the default one. A plane knows where a third of the way between two points is; a table of pairwise distances does not, and neither does a network whose places are junctions rather than coordinates. Returning null is how such a model says so, and machinery that interpolates -- InterpolatedMovement -- then makes a journey a single step: the vehicle waits out the whole leg and arrives, which is what a free-path move has always done.

A model that overrides this must return a location valid within itself, and must satisfy interpolate(a, b, 0.0) == a and interpolate(a, b, 1.0) == b by its own compareLocations.

Parameters