The following bug has been logged online:
Bug reference: 5745
Logged by: Jin
Email address: jindiax(at)gmail(dot)com
PostgreSQL version: 8.4.5
Operating system: windows xp pro sp3
Description: geometry bug?
Details:
The distance of the horizontal lseg and the point on that is inaccurate.
select point(1.0,1.0) <-> lseg'(0.0,0.0),(2.0,0.0)';
↓
result 1.4142135623731
must be 1.0
P.S.
I'm sorry about if it was already reported.
Because I can't read English well.