[postgis-users] More information on the new curve type

[Paul Ramsey]

Right now, because we don't do any operations on the curves, just 
indexing and input/output, they can be said to "support" any 
interpolation type you want... all we store are three control points for 
each curve segment, you can interpret what happens between them how you 
like.

However, once we start implementing operations, you'll find that the 
interpolation type is circular arc, as specified by ISO.  That doesn't 
stop you from using the storage/input/output routines and they doing any 
operations outside the database in a tool that understands your 
interpolation type.

Once you say "curve" everyone starts leaping up and down, asking about 
their favourite interpolation type (Spline! No, clothoid! No, circle! No 
bezier!), and I am not sure how to satisfy that demand without embarking 
on a 10 year development project.  Anyone have any ideas?

Paul

Andreas Neumann wrote:
> Hello,
> 
> I am interested in the new curve type. Is there any information (either 
> by ISO/Opengeospatial or Refractions) available with some examples?
> 
> Specifically, what geometry does the "curve" type support? Does it 
> support spline curves (if yes, which ones) or arc segments? I understand 
> that curve is sort of a superclass of Linestring, etc., but does it also 
> support more complex curves like splines/beziers?
> 
> Thanks for any information,
> Andreas
> 


-- 

   Paul Ramsey
   Refractions Research
   http://www.refractions.net
   pramsey at refractions.net
   Phone: 250-383-3022
   Cell: 250-885-0632