note BrowserUk <blockquote><i></i></blockquote> <p>Given that the area between the +-70&deg; latitudes covers 95% of the Earth's surface and 99.8% of the world's population; and the 0.2% inaccuracy represents a 0.00016 mm on a standard large scale (1::25,000) map -- or, you'd need a map 800 meters wide in order to be able to detect the inaccuracy between the actual and calculated position of a point -- the "general case" is not required for the vast majority of cases. <p>Hence why I passed along the information that the general case is not usually required, without in any way impugning the accuracy of your post. <p>I was simply pointing out that unless you run an airline -- and one hopes they know what they are doing -- the simple 2D trig approach to mapping GPS coordinates to map coordinates is usually good enough. <div class="pmsig"><div class="pmsig-171588"> <hr /> <font size=1 > <div>With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'</div> <div>Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.</div> <div>"Science is about questioning the status quo. Questioning authority". </div> <div>In the absence of evidence, opinion is indistinguishable from prejudice. </div> </font> </div></div> 1012321 1012503