
5th Oct 2006, 09:06

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Excel Distance Calculator Formulae
Hi guys, Would anyone happen to know where I can find a ready made formula for Excel that can calculate the distance between 2 sets of WGS84 Lat and Long coordinates? Cheers,
Ox



5th Oct 2006, 11:57

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5th Oct 2006, 12:32

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Not familiar with WGS84 coordinates, but that looks like the calculation I use:
=SUM(60*ACOS((SIN(Lat1*PI()/180)*SIN(Lat2*PI()/180)+COS(Lat1*PI()/180)*COS(Lat2*PI()/180)*COS((Long2Long1)*PI()/180)))*180/PI())
(which you can cut and paste directly into a cell) where one point is at Lat1, Long1 and the other is at Lat2, Long2. The result is in nautical miles.
As the comment in the reference says, you have to convert degrees, minutes and seconds to decimals of degrees, although there is probably a quick way around this that I haven't bothered with. You also have to be careful when the points are on opposite sides of 0 or 180 degrees longitude or of the equator  in each case one set of numbers has to be negative, the other positive. For example, taking west of the Greenich meridian and south of the equator as negative; Manchester is +53.50, 2.25 Kuala Lumpur is +3.13, +101.70 Santiago de Chile is 33.50, 70.67
If I remember correctly, I got that out of the instruction book for a Hewlett Packard HP35 calculator in the 1980s!
GG
Last edited by Groundgripper; 5th Oct 2006 at 12:51.
Reason: Edited for clarity (and history!)



5th Oct 2006, 13:30

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That's perfect Groundgripper, thanks very much! Also thanks to mdc for your time as well



6th Oct 2006, 13:46

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Now on to the next challenge  an Excel formula to work out the track between two sets of coordinates. Any ideas Groundgripper?
Cheers



6th Oct 2006, 14:27

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[pedantic mode on] The formula provided does not provide distance on a WGS84 sphereiod, but on a standard sphere. One's round, that other one's roundish.[/pedantic mode off]



6th Oct 2006, 17:17

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Although not exactly what you were looking for, this site will produce great circle distances between lat/long points and by various aviation designators.
http://gc.kls2.com/



7th Oct 2006, 17:44

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Oxeagle,
On the previous link I've mentioned I thought there was formula to calculate this.



8th Oct 2006, 10:29

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Hi OA
This is what I use. Sorry about the brackets!
Initial True Track = arcos [ (sin LatB  sin LatA* cos(Dist/60))/(sin (Dist/60) cos LatA)]
if sin (LongA  LongB) < 0
then (360Initial True Track)
is used
Where:
Start Position Lat A Long A
Finish Position Lat B Long B
Last edited by Mornington Crescent; 8th Oct 2006 at 10:36.
Reason: Update



8th Oct 2006, 22:25

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Quote:
Now on to the next challenge  an Excel formula to work out the track between two sets of coordinates. Any ideas Groundgripper?

Er, no! And sorry for the delay in responding  busy this weekend. As you will have seen, there are greater minds than mine responding to your query. Stoney X: yes, I realised that it was for a true sphere but had (and still have) no idea about what difference that would make  my interest has never required that accurate an answer! I did google on WGS84 and read this article in Wikipedia, but halfway through everything went blurred and I had to go and have a liedown in a darkened room for a time! GG



9th Oct 2006, 10:09

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mdc  yes I noticed the website had code for calculating a track, but it's in VB/NET script and I do not posses the technical knowledge nor the programs to use it! Morning Crescent  That's the formula i'm looking for, but it's just a case of converting it to an Excel formulae Groundgripper  no problem, thanks for your help with the distance formula!



9th Oct 2006, 14:16

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OA
Check your PMs
MC



18th Oct 2006, 16:24

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Ok, so i've managed to put together a distance and bearing calculator with extremely valuable help and advice from you guys, so many thanks However, I have now hit another problem. Originally when I had completed it, the bearing calculator was working perfect give or take half a degree or so, but if the track crossed the meridian the distance calculator strated spewing random numbers at me. Managed to correct that, but now the track headings go out the window when the track crosses the meridian!
Anyone have any ideas? I have tried everything I can think of and more over the last week, i've checked every bit of coding 3 of 4 times, and I still can't work it out. It's enough to make you loose the will to live!
If anyone could shed any light on this problem, I would be extremely grateful
Cheers,
Ox



18th Oct 2006, 18:17

#14 (permalink)

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Aviation Formulary V1.43



20th Oct 2006, 16:00

#15 (permalink)

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Finally figured out what was going wrong! I now have a fully working distance and track calculator. Many thanks guys, couldn't have done it without the help I recieved for you lot!
Ox



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