> On 11 Apr 2020, at 12:24 AEST, John J Foster via 4D_Tech > <4d_tech@lists.4d.com> wrote: > > Couldn’t find anything in KB.
Here is the post from 155 month and 19 days ago mentioned in the other post: <REPOST> But someone might think the following could be of some help, sorry its not 4D-code. First, the orientation - <http://en.wikipedia.org/wiki/ Cardinal_direction> N (North) - E (East) - S (South) - W (West) N=0° - E=90° - S=180° - W=270° All computers and programming languages I know are handling angles the 'Mathematic Way' witch makes sense! Every trigonometric function can be described/build by more simpler trigonometric functions. For trigonometric functions look here: <http://en.wikipedia.org/wiki/ Trigonometric_function> It is possible to calculate bearing and direction from 'A' to 'B' and find 'B' if bearing and distance is known. The following is my own translation of my own posting placed in a German GPS news-group a long time ago. *************** Definitions nm = Nautical Mile = 1852 m alpha = Bearing d = distance in [nm] !!!! b = latitude difference between ‘A’ and ‘B’ l = longitude difference between ‘A’ and ‘B’ a = Abweitung <http://de.wikipedia.org/wiki/Abweitung> just in case someone wants a desicription - no English version sorry Ba = latitude of Position ‘A’ La = longitude of Position ‘A’ Bb = latitude of Position ‘B’ Lb = longitude of Position ‘B’ Bm = Mittelbreite - middle latitude??? anyone??? Krauts! ;-) <the holy grail of navigation> ;-) b =Bb-Ba l =Lb-La Bm=(Ba+Bb)/2 OR Ba + b/2 l=a*sec(Bm) (sec = 1/cos) a=l*cos(Bm) a=d*sin(alpha) b=d*cos(alpha) d=b*sec(alpha) For Longitude 85°<alpha<90° more accurate distance with --> d=a*cosec (alpha) `(cosec = 1/sin) tan(alpha)=a/b </ the holy grail of navigation> ************* </REPOST> If you need more just ask. Cheers Jörg ********************************************************************** 4D Internet Users Group (4D iNUG) Archive: http://lists.4d.com/archives.html Options: https://lists.4d.com/mailman/options/4d_tech Unsub: mailto:4d_tech-unsubscr...@lists.4d.com **********************************************************************
