DirectionFrom ( Lat1 ; Lon1 ; Lat2 ; Lon2 )

Calculates the approximate direction in cardinal (compass) points from one location on earth to another.

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Chris Pye - Show more from this author
Mactec
http://www.mactec.com.au

Sample input:

DirectionFrom ( -27.603479 ; 152.823141 ; -28.088477 ; 153.451921 )

Sample output:

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

/*

Calculates the approximate direction in cardinal (compass) points from one location on earth to another.

Latitude and Longitude are entered in decimal degrees.

*/

Let (

[ 

LatDiff = Lat2 - Lat1 ;

LonDiff = Lon2 - Lon1;

TotalDiff = Abs (LatDiff) + Abs (LonDiff) ;
LatPercent = ( Abs (LatDiff) / TotalDiff) * 100  ;
LonPercent = ( Abs (LonDiff) / TotalDiff) * 100 ;

LatDir = Case ( LatDiff > 0 ; "N" ; LatDiff < 0 ; "S" ; "" );

LonDir = Case ( LonDiff > 0 ; "E" ; LonDiff < 0 ; "W" ; "" )

] ; 

Case (LatPercent > LonPercent and LonPercent > 25 ; LatDir & LonDir ; LonPercent > LatPercent and LatPercent > 25 ; LatDir & LonDir ; LatPercent > LonPercent ; LatDir ; LonPercent > LatPercent ; LonDir ; "" )

)

I use this function along side Vaughan Bromfield's "DistanceBetweenPoints" custom function http://www.briandunning.com/cf/143 to calculate the distance and direction between two locations.

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Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

DirectionFrom ( Lat1 ; Lon1 ; Lat2 ; Lon2 )

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