A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2014 Dec 1, 06:45 -0800
I use cosine of the latitude so that at 34° N a 10' spread of latitude will be 8.3' of latitude per 10' of longitude. For short distances there is no need to get fancy with meridianal parts which takes into account a bulging equator.