## LatLonForCourseAndDistance(lat1, lon1, tcl, d)

##### Last updated May 16, 2002

**Version:** 1 |
**Requires:** CF5 |
**Library:** MathLib

**Description:**

Calculates the latitude and longitude for a given latitude, longitude, true course and distance. Calculates complete latitude and longitude for a given position, true course and distance in NAUTICAL MILES!

**Return Values:**

Returns a string containing the latitude and longitude.

**Example:**

```
<cfoutput>
Example:<br>
Suppose point 1 is LAX: (33deg 57min N, 118deg 24min W)<br>
True course = 066 degrees<br>
Distance = 100 Nautical Miles<br>
Lat1 = 33.95 // calculated from: (33 + 57/60)<br>
Lon1 = 118.4 // calculated from: (118 + 24/60)<br>
<cfset pair = LatLonForCourseAndDistance(33.95,118.4,66,100)>
#listfirst(pair)# = 34degrees 37min N<br>
Lon = #listlast(pair)# = 116 degrees 33min W<br>
</cfoutput>
```

**Parameters:**

Name | Description | Required |
---|---|---|

lat1 | Latitude of the first point in degrees. | Yes |

lon1 | Longitude of the first point in degrees. | Yes |

tcl | True course. | Yes |

d | Distance in nuatical miles from lat1/lon1. | Yes |

**Full UDF Source: **

```
/**
* Calculates the latitude and longitude for a given latitude, longitude, true course and distance in nautical miles.
* This function uses forumlae from Ed Williams Aviation Foundry website at http://williams.best.vwh.net/avform.htm.
*
* @param lat1 Latitude of the first point in degrees. (Required)
* @param lon1 Longitude of the first point in degrees. (Required)
* @param tcl True course. (Required)
* @param d Distance in nuatical miles from lat1/lon1. (Required)
* @return Returns a string containing the latitude and longitude.
* @author Tom Nunamaker (tom@toshop.com)
* @version 1, May 16, 2002
*/
function LatLonForCourseAndDistance(lat1,lon1,tc,d) {
var lat = 1;
var lon = 1;
tc = tc * pi() / 180;
d = d * pi()/(180*60);
lat1 = lat1 * pi()/180;
lon1 = lon1 * pi()/180;
lat = asin(sin(lat1)*cos(d)+cos(lat1)*sin(d)*cos(tc));
if (abs(lat) IS pi()/2) lon = lon1;
else lon = properMod(lon1-asin(sin(tc)*sin(d)/cos(lat))+pi(),2*pi()) - pi() ;
lat = lat * 180/pi();
lon = lon * 180/pi();
return lat & "," & lon;
}
```

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