[gradsusr] Calculate distance between latitude-longitude in GrADS

[PHILBERT LUHUNGA]

 Hi Davide, I learned the script but the final part of the script is not clear to me     Alpha='acos ( cos ( 'Phi1' ) *cos ( 'Phi2') +
cos ( 'Theta1'-'Theta2' ) *sin ( 'Phi1' ) *sin ( 'Phi2'))'
*    'd asin ( sqrt ( 'd2'))'
*    'd acos ( 'Alpha')'
    ' d 'Alpha
*say 'T , P: 'Theta1' 'Phi1
*say 'T , P: 'Theta2' 'Phi2
*say 'A , cA : 'Alpha' 'subwrd ( result , 4)
  return (subwrd ( result , 4 ) *_At)   
  what is a distance then. is it *    d2=x*x+y*y+z*z?
AS EVER
LUHUNGA

--------------------
Philbert Modest Luhunga
University of Pretoria 
Department of Geography,Geoinformatics and Meteorology
Private Bag X20 Hatfield 0028 South Africa
Tel +27 (0) 12 420 5164
Fax +27 (0) 12 420 6385
Mobile:+ 27826228060
Email address: philuhunga at yahoo.com
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