[Proj] Optimal Albers Standard parallels

[strebe at aol.com]

Apologies for the long delay in responding. Determining the optimal Lambert azimuthal equal-area is equivalent to solving the "minimum covering circle problem" described here:

http://en.wikipedia.org/wiki/Smallest_circle_problem

Apparently it can be solved in linear time by an algorithm due to Meggido. This is unexpectedly (to me)  efficient. However, I have not examined the algorithm itself yet; technically the optimal LAEA problem is not QUITE the equivalent to the "minimum covering circle problem" unless the latter requires in its solution not only the radius of the circle, but also its location. The radius is irrelevant to the optimal LAEA problem; it is the center point that is required.

Regards,
— daan Strebe


 

 

-----Original Message-----
From: Jan Hartmann <j.l.h.hartmann at uva.nl>
To: PROJ.4 and general Projections Discussions <proj at lists.maptools.org>
Cc: strebe <strebe at aol.com>
Sent: Mon, Feb 22, 2010 3:04 am
Subject: Re: [Proj] Optimal Albers Standard parallels


  For me, I certainly would be interested in the algorithm.

Jan

On 21-2-2010 20:41, strebe wrote:
  

  
  
Oscar: