-----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Barend Gehrels Sent: Thursday, January 31, 2008 11:55 AM To: boost@lists.boost.org Subject: Re: [boost] preview of a template geometry library
Hervé,
Thanks for your reaction. I will consider the separation of core geometry and more GIS-like geometries, and will study on your idea of coordinate-free geometries.
We had the feeling that a library user or implementer can always speciliaze for other points than x-y, so it would work, but indeed if you have to redo all algorithms for latlong it is quite a job.
Another wrinkle for latlon conversion is that there are two different latitudes. This results from the earth being an ellipsoid rather than a sphere (centrifugal force makes the equator bulge out more than the poles). The "geodetic" latitude is the angle from the equator to a line perpendicular to the local earth surface. The "geocentric" latitude is the angle is from the equator to a line that intersects the center of the earth. The geodetic latitude is the one used most often but there are uses for the other one. -ges