PRO compass,az_string,barlength,fac,psres

csz=0.75*fac
nflag=isnumber(az_string,azimuth)

IF nflag NE 0 THEN BEGIN 	; if the camera azimuth is known,
    azrad=!DTOR*azimuth		; plot arrows showing the azimuth
    leftend=7*csz*!D.X_CH_SIZE
    maxlen=(leftend-scl(res=psres,1.5*csz*!D.X_CH_SIZE)) $
           /scl(res=psres,(COS(azrad)+SIN(azrad))*csz*!D.Y_CH_SIZE)
    arlen=MIN([FIX(maxlen),5])*csz*!D.Y_CH_SIZE
    tailx=REPLICATE(scl(res=psres,0.5*csz*!D.X_CH_SIZE+SIN(azrad)*arlen),2)
    taily=REPLICATE(scl(res=psres,barlength),2)
    headx=[tailx(0)-scl(res=psres,arlen*SIN(azrad)), $
           tailx(1)+scl(res=psres,arlen*COS(azrad))]
    heady=[scl(res=psres,barlength+arlen*COS(azrad)), $
           scl(res=psres,barlength+arlen*SIN(azrad))]
    arrow,tailx,taily,headx,heady,/device,hsize=-0.2
    XYOUTS,headx(0)+scl(res=psres,csz*!D.X_CH_SIZE) $
          ,MIN([heady(0),scl(res=psres,!D.Y_SIZE-csz*!D.Y_CH_SIZE)]) $
          ,'N' $
	  ,ALIGNMENT=0,/DEVICE,CHARSIZE=csz,CHARTHICK=csz
    XYOUTS,headx(1)+scl(res=psres,csz*!D.X_CH_SIZE) $
	  ,heady(1) $
	  ,'E' $
          ,ALIGNMENT=0.5,/DEVICE,CHARSIZE=csz,CHARTHICK=csz
    ENDIF ELSE BEGIN		; otherwise show cardinal directions
    XYOUTS,scl(res=psres,3*csz*!D.X_CH_SIZE) $
          ,scl(res=psres,!D.Y_SIZE-csz*!D.Y_CH_SIZE) $
          ,'N' $
	  ,/DEVICE,ALIGNMENT=0.5,CHARSIZE=csz,CHARTHICK=csz
    XYOUTS,scl(res=psres,csz*!D.X_CH_SIZE) $
          ,scl(res=psres,!D.Y_SIZE-2.5*csz*!D.Y_CH_SIZE) $
	  ,'W' $
          ,/DEVICE,ALIGNMENT=0.5,CHARSIZE=csz,CHARTHICK=csz
    XYOUTS,scl(res=psres,5*csz*!D.X_CH_SIZE) $
          ,scl(res=psres,!D.Y_SIZE-2.5*csz*!D.Y_CH_SIZE) $
	  ,'E' $
          ,/DEVICE,ALIGNMENT=0.5,CHARSIZE=csz,CHARTHICK=csz
    XYOUTS,scl(res=psres,3*csz*!D.X_CH_SIZE) $
          ,scl(res=psres,!D.Y_SIZE-4*csz*!D.Y_CH_SIZE) $
	  ,'S' $
	  ,/DEVICE,ALIGNMENT=0.5,CHARSIZE=csz,CHARTHICK=csz
    ENDELSE

RETURN
END