[postgis-users] Hobbyist question about curves

[h]

Hi,
I use PostGIS and QGIS on an OpenSUSE machine with a fairly light level
of expertise.

I am interested in roads, and would like to be able to see / examine
curves / bends.

I have downloaded roads from OSM  (nodes and ways), brought these into
PostGIS as CSV files and am able to display them in
QGIS.St_LinetoCurve(lineGeom)

What I would like to do is convert these lines into curves.  I have
tried using "St_LinetoCurve(lineGeom)" to form the curves, but the
geometry returned appears identical to the original lines.

My main assumption is that if I pass St_LinetoCurve a line string,
it will return a multigeometry object containing lines and circular
arcs.

How can I convert a line string into a collection of lines and circular
arcs?

Also, once this is done, is there a command to return the radius of the
circular arcs created?


Many thanks

hdixon