% gdcntr

 GEMPAK-GDCNTR> HILO     =
 GEMPAK-GDCNTR> FLINE = 0;30-7
 GEMPAK-GDCNTR> fint = 2/6
 GEMPAK-GDCNTR> scale = 9                  
 GEMPAK-GDCNTR> gfunc = adv(avor(wnd),wnd) 
 GEMPAK-GDCNTR>l                           
 GDATTIM  = f000
 GLEVEL   = 500
 GVCORD   = pres
 GFUNC    = adv(avor(wnd),wnd)
 GDFILE   = $HDS/96022112_eta.gem
 CINT     = 0
 LINE     = 4
 MAP      = 15/1/2
 TITLE    = 1/-1
 DEVICE   = xw
 SATFIL   = 
 RADFIL   = 
 PROJ     = lea/45;-100;0
 GAREA    = #33;-90;20;40
 CLEAR    = y
 PANEL    = 0
 TEXT     = 1.3/23//hw
 SCALE    = 9
 LATLON   = 0
 HILO     = 
 HLSYM    = 3/2/22/1/hw
 CLRBAR   = 
 CONTUR   = 3/0
 SKIP     = 0
 FINT     = 2/6
 FLINE    = 0;30-7
 CTYPE    = f
 GEMPAK-GDCNTR>r

Why is the first color "0" in the FLINE definition?