Re: Distance between 2 WGS84-LatLon Coordinates

Hi,

The com.bbn.openmap.proj.GreatCircle class does have methods that
perform distance (and other calculations) based on a spherical model of
the Earth. You can use the com.bbn.openmap.proj.Length class (and it's
internal defined instances) to convert the output of the GreatCircle
class to units.

- Don

On Thursday, March 7, 2002, at 10:07 AM, Chris Hopkins wrote:

>
> Hi -
>
> I'm not sure if the WGS84 distinguishes the coordinates from regular
> coordinates, but here is a method which computes (estimates really) the
> distance between two lat/lon coordinates:
>
> // 6367 is "standard" radius of earth in km
> // 1.852 is km per Nautical Mile; this converts R to radius in naut
> miles
> private final static double R = 6367.0 / 1.852;
> private final static double RADIANSPERDEGREE = 0.017453293;
>
> private double computeDistance(double lat1, double lon1, double lat2,
> double lon2)
> {
> // all values are of type "double"; lat1,lon1,lat2 and lon2 are the
> // coordinates we are using in the calculation, in RADIANS.
> // You will have to convert from degrees to radians using the
> // conversion factor, RADIANSPERDEGREE
> lat2 = lat2 * RADIANSPERDEGREE;
> lon2 = lon2 * RADIANSPERDEGREE;
>
> double dlon = lon2 - lon1; // difference in longitude
> double dlat = lat2 - lat1; // difference in latitude
>
> double a = (Math.sin(dlat/2.0)* Math.sin(dlat/2.0)) +
> (Math.cos(lat1) * Math.cos(lat2) *
> Math.sin(dlon/2.0) * Math.sin(dlon/2.0));
>
> double c = 2.0 * Math.asin(Math.sqrt(a));
>
> return (R * c); // Final distance is in nautical miles.
> }
>
> Hope that helps. I couldn't find any means of calculating distances
> between
> two lat/lon points in OpenMap so I borrowed one from the net. This
> gives the
> result in nautical miles.
>
> - Chris
>
>> -----Original Message-----
>> From: owner-openmap-users@bbn.com [mailto:owner-openmap-
>> users@bbn.com]On
>> Behalf Of Gubler, Rüdiger
>> Sent: Thursday, March 07, 2002 8:57 AM
>> To: Openmap-Users (E-Mail)
>> Subject: Distance between 2 WGS84-LatLon Coordinates
>>
>>
>>
>> Hello,
>>
>> in which way can i calculate the distance
>> between two WGS84-LatLon Coordinates?
>>
>>
>> Thanks Rüdiger
>>
>> --
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>
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>
>

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Don Dietrick, dietrick@bbn.com
BBN Technologies, Cambridge, MA
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

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