[postgis-users] ST_LineToCurve for less than 4 points

[Stephen Woodbridge]

On 2/28/2012 3:38 AM, Sandro Santilli wrote:
> On Tue, Feb 28, 2012 at 09:36:34AM +0100, Denis Rouzaud wrote:
>> Hi,
>>
>> Can someone tells me why ST_LineToCurve needs at least a linestring
>> of 4 points to be run?
>> If I have three points, I should be able to create a circularstring, right?
>>
>> Here the error I have:
>> SELECT ST_LineToCurve(ST_GeomFromText('LINESTRING(554803.177682475
>> 145390.853708235,554796.469135702 145401.404724093,554769.634948609
>> 145404.042478058)'));
>> ERROR:  pta_desegmentize needs implementation for npoints<  4
>
> If I read the message correctly it answers exactly your questions.
> It "needs implementation". A patch is welcome.

Is this the algorithm that is needed to solve this?
http://paulbourke.net/geometry/circlefrom3/

-Steve