;+
; NAME:
;	CONVERT
; PURPOSE:
;       Conversion from geographic coordinates to PACE geomagnetic
;       coordinates (cf. Baker, K.B. and S. Wing, J. Geophys. Res.,
;       Vol. 94, pg. 9139, 1989) (PACE => Polar Anglo-american
;	Conjugate Experiment)
; CATEGORY:
;	Coordinate conversion
; CALLING SEQUENCE:
;	CONVERT,YR,MON,DAY,HR,MIN,SEC,LAT,LON,ALT $
;	       ,MLAT,MLT
; INPUTS:
;	YR, MON, DAY:	Specify the date (in Universal Time);
;	HR, MIN, SEC:	Specify the time (in Universal Time);
;       LAT, LON, ALT:  Specify the location (in degrees of N
;                       geographic latitude, E longitude, and
;			kilometers).
; OPTIONAL INPUTS:
;	None.
; KEYWORD PARAMETERS:
;	None.
; OUTPUTS:
;       MLAT, MLT:      Return the geomagnetic latitude and magnetic
;			local time (hours) of the specified location.
; OPTIONAL OUTPUTS:
;	None.
; COMMON BLOCKS:
;	None.
; SIDE EFFECTS:
;       Three files are written in ~steele/PACE: scratch0.dat holds
;       the input parameters, scratch1.dat holds the output
;       parameters, and checkinp.dat holds the inputs as well as
;	all parameters generated by the SPAWNed executable.
; RESTRICTIONS:
;	PACE doesn't work for altitudes above 600 km.
; PROCEDURE:
;       The inputs are written to a formatted file: scratch0.dat.
;       An executable file is run via SPAWN, which reads the inputs,
;       performs geographic->PACE conversion on them, and writes
;       the MLAT and MLT to another formatted file: scratch1.dat.
;       The contents of this file are then returned to the calling
;	IDL routine.
; EXAMPLE:
;	IDL> convert,1995,2,7,16,30,0,51.0800,245.8681,1.1154,mlat,mlt
;	IDL> PRINT,mlat,mlt
;	      58.6273      7.90959
; SEE ALSO:
;	
; MODIFICATION HISTORY:
; 	Written by:	R A Doe, SRI International, 1993?
;	Modified:	D P Steele, ISR, U of Calgary, 950207.
;-
PRO convert,yr,mon,day,hr,min,sec,lat,lon,alt,mlat,mlt

;  This program is an IDL driver for the PACE geomagnetic
;  model of Baker and Wing.  UT hour, minute and seconds, as well
;  as geographic latitude, longitude and altitude are written to
;  a file scratch0.dat.  The program then spawns out to the FORTRAN
;  executable `convert' which converts the input coordinates to
;  PACE geomagnetic latitude and magnetic local time.  MLAT and MLT
;  are then written to a file scratch1.dat and control passes back
;  to the IDL program.

CD,'~cnsr3/pace',CURRENT=old_dir

OPENW,1,'scratch0.dat'
PRINTF,1,FORMAT='(6(2x,i2),2x,f6.2,2x,f7.2,2x,f7.2)' $
	,yr MOD 1900,mon,day,hr,min,sec,lat,lon,alt
CLOSE,1

SPAWN,"convert",/NOSHELL

OPENR,1,'scratch1.dat'
READF,1,mlat,mlt
CLOSE,1

CD,old_dir

RETURN
END