[postgis-devel] Distance operator in presence of M

[Sandro Santilli]

On Fri, Jun 05, 2015 at 09:17:12AM +0200, Havard Tveite wrote:

> For operations involving distance calculations, you need to have
> a way to compare space+time "distances".  Which is closest of two
> points where the spatial distances are 200m and 250m while the
> temporal distances are 80 seconds and 60 seconds?
> As Greg says, for that you need to have a velocity.
> If velocity is supplied as a parameter, it could be possible to
> support such operations.

Indeed my work on space+time is currently based on "trajectories"
which encode not only velocity but also direction (needed as well).

--strk;