Perceived motion between two nearby poses: √(ρ²·pan² + zoom²/ρ² + turn²) with
pan the target displacement in view heights (at the mean distance), zoom the
change in log distance (or log ortho zoom), turn the change of view direction
in radians. With ρ = √2 this is van Wijk & Nuij's metric, under which their
zoom-pan path moves at constant speed; turning is added at par with panning.
Perceived motion between two nearby poses: √(ρ²·pan² + zoom²/ρ² + turn²) with pan the target displacement in view heights (at the mean distance), zoom the change in log distance (or log ortho zoom), turn the change of view direction in radians. With ρ = √2 this is van Wijk & Nuij's metric, under which their zoom-pan path moves at constant speed; turning is added at par with panning.