[postgis-users] Looking for help / documentation on curves

[h]

Hi
I am wanting to use curves (arcs) for representing roadways.
I am having trouble finding documentation on curves.

My googling brings up articles like:

https://gip.itc.nl/default/node/75

and others dated around 2012.

Can someone direct me to some current tutorials or documentation on
using curves in PostGIS?

I am particularly interested in calculating radii, but would appreciate
a general article on curves..

Many thanks,
H