Can we access the publication for free? Someone changed the link, originally it was:
https://scibib.dbvis.de/uploadedFiles/MotionRugsPreprint.pdf
"For the Z-Order Curve we found that it is prone toproduce “Phantom-Splits”, visual artifacts creating the impression of a physical split of the entities when there is none. The Hilbert Curve insteaddisplays the spatial dynamic better than the Point-QuadTree and shows fewer artifacts than the Z-Order."