Converting GPS Data

Device 16F876
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; MAIDENHEAD Grid Locator
;================================================= ===================================
;USE: After you successfully read the GPS Data via LES's GPS Parsing routine example
; then just make a GOSUB Maidenhead which allows you to get the needed characters
; and digits used to express a MAIDENHEAD Grid Locator (i.e. KL28PE ).
;================================================= ===================================
;--- LES's Parse GPS demo Dims ------------------------------------------------------
Dim LATITUDE_DEGREES As Byte ;if those are allready declared in your code
Dim LATITUDE_MINUTES As Byte ;namely LES GPS Parsing routine
Dim LATITUDE_SECONDS As Word ;then kindly remove them from here
Dim LONGITUDE_DEGREES As Byte ;
Dim LONGITUDE_MINUTES As Byte ;
Dim LONGITUDE_SECONDS As Word ;
;---- MAIDENHEAD Dims ---------------------------------------------------------------
Dim lat1 As Float
Dim lat2 As Float
Dim lat3 As Byte
Dim lat4 As Byte
Dim lat5 As Byte
Dim lon1 As Float
Dim lon2 As Byte
Dim lon3 As Byte
Dim lon4 As Byte
Dim lon5 As Float
Dim lon5b As Byte
Dim let1 As Byte
Dim let2 As Byte
Dim let3 As Byte
Dim let4 As Byte
Dim let5 As Byte
Dim let6 As Byte
Dim llon2 As Byte
Dim llat3 As Byte
Dim llon3 As Byte
Dim llat4 As Byte
Dim llon5 As Byte
Dim llat5 As Byte
'----- Subroutine -------------------------------------------------------------------
maidenhead:
lat1 = LATITUDE_SECONDS / 3600
lat1 = lat1 + LATITUDE_MINUTES / 60
lat1 = lat1 + LATITUDE_DEGREES
lat1 = 90 + lat1 ; (+) if NORTH only - else (-) insert your code here for N or S comparison
;lat1 = 90 - lat1 ; use like that for South
lat3 = Abs (lat1 /10) ;used for second letter
lat4 = lat3 * 10 ;
lat4 = Abs (lat1 - lat4); used for second digit OK
lat2 = lat1 - (lat3 * 10) ;
lat2 = lat2 - lat4 ;
lat5 = Abs (lat2 * 24) ; used for forth letter
lon1 = LONGITUDE_SECONDS / 3600 ;
lon1 = lon1 + LONGITUDE_MINUTES / 60 ;
lon1 = lon1 + LONGITUDE_DEGREES ;
lon1 = 180 + lon1 ; (+) if EAST only - else (-) insert your code here for E or W comparison
;lon1 = 180 - lon1 ; use like that for West
lon2 = lon1 / 20 ; first letter
lon3 = lon2 * 20 ;
lon3 = Abs ((lon1 - lon3)/2) ; first digit
lon4 = lon1 ;
lon4 = lon4 // 2 ;
lon5 = 20 * lon2 ;
lon5b = lon1 ;
lon5 = lon1 - lon5b ;
lon5 = Abs ((lon5 + lon4)* 12); third letter
lon5b = lon5 ; if these lines should be removed then change accordingly
llon2 = lon2 ; the next LOOKUPL variables, but
llat3 = lat3 ; the main purpose for them is to transfer the integer part of a floating
llon3 = lon3 ; variable into a word or byte variable. Can be done also differently but
llat4 = lat4 ; we don't discuss that here
llon5 = lon5b;
llat5 = lat5 ;
let1 = LookUpL llon2 , ["ABCDEFGHIJKLMNOPQRSTUVWXYZ"] ;1st character position 1
let2 = LookUpL llat3 , ["ABCDEFGHIJKLMNOPQRSTUVWXYZ"] ;2nd character position 2
let3 = LookUpL llon3 , ["0123456789"] ;1st digit position 3
let4 = LookUpL llat4 , ["0123456789"] ;2nd digit position 4
let5 = LookUpL llon5 , ["ABCDEFGHIJKLMNOPQRSTUVWXYZ"] ;3rd character position 5
let6 = LookUpL llat5 , ["ABCDEFGHIJKLMNOPQRSTUVWXYZ"] ;4th character position 6
Return
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