precision issue with very small spoly

[pdowler]

I am trying to insert very small polygons. I can insert a polygon with micro-radians (1e-6) coordinate values:

select '{(0.0,-0.000001),(6.283184,0.0),(0.0,0.000001),(0.000001,0.0)}'::spoly;
                         spoly                         
-------------------------------------------------------
 {(0 , -1e-06),(6.283184 , 0),(0 , 1e-06),(1e-06 , 0)}

When I try nano-radians (1e-9) the parser seems to consider some points as equal:

select '{(0.0,-0.000000001),(6.283185306,0.0),(0.0,0.000000001),(0.000000001,0.0)}'::spoly;
ERROR:  spherepoly_from_array: more than two points needed

Are the parser/internals using single-precision/float instead of double?