;Title:		readsat_overpass.pro
;
;Purpose:	To read in the satellite overpass times for all available platforms with viewing angles less than
;				a designated angle.
;
;Inputs:	arg:	Date of interest:  YYYYMMDD
;
;Outputs:
;
;Author:	Matthew Shupe
;Date:		4/18/01
;Modified:	6/4/02	;for sheba
;--------------------------------------------------------------------------------
pro readsat_overpass,arg,platform,sattime,viewzen

anglelimit=30
yy=strmid(arg,2,2)
mm=strmid(arg,4,2)
dd=strmid(arg,6,2)

; The platforms
platforms=['NOAA_12','NOAA_14']
sattime=0.0
viewzen=99.0
platform='NONE'
v1=' ' & v2=v1 & v3=v1 & v4=v1 & v5=v1 & v6=v1

for p=0,n_elements(platforms)-1 do begin
	arg='SHB_'+platforms[p]+'.txt'
	file=findfile(arg)
	openr,lun,/get_lun,file[0]
	v1='80'
	while v1 ne yy and not(eof(lun)) do readf,lun,v1,v2,v3,v4,v5,v6,format='(3X,A2,1X,A2,1X,A2,1X,A2,1X,A2,6X,A5)'
	if not(eof(lun)) then begin
		if fix(v2) lt 10 then v2f='0'+strmid(v2,1,1) else v2f=v2
		while v2f ne mm and not(eof(lun)) do begin
			readf,lun,v1,v2,v3,v4,v5,v6,format='(3X,A2,1X,A2,1X,A2,1X,A2,1X,A2,6X,A5)'
			if fix(v2) lt 10 then v2f='0'+strmid(v2,1,1) else v2f=v2
		endwhile
		if not(eof(lun)) then begin
			if fix(v3) lt 10 then v3f='0'+strmid(v3,1,1) else v3f=v3
			while v3f ne dd  and not(eof(lun)) do begin
				readf,lun,v1,v2,v3,v4,v5,v6,format='(3X,A2,1X,A2,1X,A2,1X,A2,1X,A2,6X,A5)'
				if fix(v3) lt 10 then v3f='0'+strmid(v3,1,1) else v3f=v3
			endwhile
			if not(eof(lun)) then begin
				tm=0.0
				vz=99.0
				while v3f eq dd do begin
					tm=[tm,float(v4)+float(v5)/60.0]
					vz=[vz,float(v6)]
					readf,lun,v1,v2,v3,v4,v5,v6,format='(3X,A2,1X,A2,1X,A2,1X,A2,1X,A2,6X,A5)'
					if fix(v3) lt 10 then v3f='0'+strmid(v3,1,1) else v3f=v3
				endwhile
				sattime=[sattime,tm]
				viewzen=[viewzen,vz]
				platform=[platform,strarr(n_elements(tm))+platforms[p]]
			endif
		endif
	endif
	free_lun,lun
endfor

iwh=where(viewzen le anglelimit,num)
if num gt 0 then begin
	sattime=sattime[iwh]
	viewzen=viewzen[iwh]
	platform=platform[iwh]
endif else begin
	sattime=-1
	viewzen=''
	platform=''
endelse

end