FUNCTION vu_vox_drawhlongitude, F,lng,cntr,dvox, obj_val
;+
; NAME:
;	vu_vox_drawhlongitude
; PURPOSE:
;	Internal use by vu_vox_showheliogrid only
; CATEGORY:
;	Volume Pro board
; INCLUDE:
	@compile_opt.pro			; On error, return to caller
; CALLS:
;	gridgen
; CALLED BY:
;	vu_vox_showheliogrid
; MODIFICATION HISTORY:
;	JUL-2002, Cindy Wang
;-
n = 180
P = gridgen(n, range=-n/2+[0,n-1])

P = replicate(1,3)#P

P[0,*] = lng
P[2,*] = 1

P = cv_coord(from_sphere=P, /to_rect, /degrees)

P = round( cntr+P*dvox )

F[P[0,*], P[1,*], P[2,*]] = obj_val

RETURN, F  &  END