Your explanation and your C# library itself are brilliant. I’ve made use of your library in a small application I’ve built to make a grid of points. Your code and the example made my task much easier. Thanks very much.

Cheers
S Pola

Thank you for sharing this valuable information with others!

Regards,

Roman

I just came across your implementation of Vincenty’s inverse formula.
Two points are worth mentioning:

1. Marcelo is right in his comment from June 2008. Equations 3, 4 and 6 do not have to be calculated inside the loop.
Neither Vincenty in his original paper does it, nor does the pseudo code in Wikipedia (http://en.wikipedia.org/wiki/Vincenty’s_formulae) or the online calculator on Movable Type Scripts (http://www.movable-type.co.uk/scripts/latlong-vincenty.html).

2. In line 268 you should not use the relative change abs((lambda – lambda0) / lambda) as stop criterion, since lambda is a longitude difference, which may be zero.
Calculating the distance between two point on the same meridian might well result in a division by zero. At least the algorithm iterates much to often.
Simply use abs(lambda – lambda0) instead.

Cheers
Clemens

Just wanted to say thanks for ur c# implementation of Vincenty’s formula,

cheers,
steve

Thanks so much for sharing this brilliant code, it has proved invaluable to me in several projects.
I would like to propose a small change which made the code more robust for real applications:
The function GeodeticCalculator.calculateEndingGlobalCoordinates(…) goes into an infinite loop if its distance parameter is given as 0.
I added these lines to the beginning of the function:

if (distance == 0)
{
return new GlobalCoordinates(start.getLatitude(), start.getLongitude());
}

Thanks again
Aharon

Thanks for sharing your information. I found it very intriguing, but too much for my simple question. I was wondering if you could shed some light on my problem.

I need to generate a bounding box of min and max latitude and longitude values so I can return addresses within a given radius.

I have two func’s below to return the range I need to +/- to the lon lat coordinates to establish the bounding box. However I don’t think the math is 100%

I am using the Haversine formula to generate my distance calculations and that seems to be working accurately. I investigated the Vincenty formula for distance as well but for my needs that was overkill.

My problem is that I would like my search results to be as accurate as Haversine in that the range I +/- to the lon lat coordinates takes into account the ellipsoidal curvature or the earth.

Ok, here are my func’s…please note I am not a Math professor )

static Func GetLatitudeRange = (latitude, distance) => (180.0 / Math.PI) * (distance / EARTH_RADIUS_IN_KM);

static Func GetLongitudeRange = (longitude, latitude, distance) =>
(
Math.Asin(
Math.Sin(distance / EARTH_RADIUS_IN_KM) / Math.Cos(latitude)
)
);

Many Thanks,
Markus