Dear All,


We were just compiling Boost Geometry Extension using VS 2017 64 bit and Warning Level 4.

Doing that showed a few warnings regarding size_t to int conversions which you might want to change.


It is in the file:


Line 436:

int n = boost::size(output_collection);

and Line 580

int size = 0, previous_size = 0;


We assume that both should be size_t.


Thanks a lot for all your hard work




Best regards,

Johan Doré
CTO, Vice President

M: +45 40 53 93 21
P: +45 88 20 20 88
C: Hørsholm, Denmark



From: Geometry <> On Behalf Of Chris Watts via Geometry
Sent: 31. december 2020 10:32
Cc: Chris Watts <>
Subject: [geometry] Polygons appear to have serious rounding errors


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:

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,