Geometry Boost List: [geometry] Polygons appear to have serious rounding errors

From: Chris Watts (Chris_at_[hidden])
Date: 2020-12-31 09:32:07

Hi all,

I've been trying to debug an issue with geographic_point_circle wherein I
can't seem to create a circle of radius 10 metres.

The easy-to-reproduce symptom is that the area of the circle varies greatly
with only a small change in latitude or longitude.

See this StackOverflow post for details:
https://stackoverflow.com/questions/65493910/boost-point-circle-coming-out-in-weird-shapes/

In order to produce a suitable circle of that scale, I need to use long
double in my point type, but with an epsilon of ~1mm, a regular double
ought to work fine. Is there something I'm missing about the implementation
of point_circle or bg::area that would imply that this is expected
behaviour?

Kind regards,
Chris