Hi, I want to calculate distance..

Hi all,
I am new in this group.
I want to calculate distance between two latitude,longitude.

could any one the formula..

Please help me..
Thanks

In an earlier contribution to this discussion,


Approx how far apart are the points, and how accurate do you need the answer
to be?
--
Cheers,
Roger
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Deepak wrote:


Aviation Formulary V1.44
http://williams.best.vwh.net/avform.html

Assuming you are looking for the shortest distance between
start and finish points anywhere on the globe, this is a spherical
earth formula from Aviation Formulary coded in Pascal:

{Distance calculations from (Lat1, Lon1) to (Lat2, Lon2)}

function GcDis(const Lat1, Lon1, Lat2, Lon2: Double): Double;
begin
Result :=3D 2*ArcSin(Sqrt(Sqr(Sin((Lat1-Lat2)/2)) +
Cos(Lat1)*Cos(Lat2)*Sqr(Sin((Lon1-Lon2)/2))));
end

You need to convert lat and lon to radians and then convert the
result from radians to your distance units. The spherical earth
model can be in error by several percent depending on the the
direction between the start and finish points.

This formula is very well behaved for small distance and handles
special cases properly.

There is a more complex formula available using the method of
Andoyer-Lambert that is more accurate for a ellipsoid shaped
earth. I have Pascal Code for it.

If the ultimate accuracy is required, you will need an iterative
algorithm such as the one developed by Thaddeus Vincenty.

Have fun.

--- CHAS

There is a free piece of software from Mentor Software called
Forward/Inverse that will do what you want to do. I don't have their
site bookmarked, but you should be able to Google them.