; this code is used to put a color bar on the map

PRO plotcolorlabel,labelname,labelcolor,pos=pos,hor=hor,_EXTRA=extra

; labelname--  string array
; labelcolor --- color index, same size as labelname

; default is vertical bar 
; pos=[xleftlow,yleftlow,xupperright,yupperright]
;         ver bar   pos=[0.88, 0.10, 0.95, 0.90] in normalize coordinates
;            hor bar pos=[0.10, 0.88, 0.90, 0.95] , default position
;               
; keywords in xyouts... can be passed

; 

n=n_elements(labelname)

x=fltarr(n)
y=x


IF keyword_set(pos) THEN BEGIN  ;pos 
x0=pos(0) & y0=pos(1)  &  xr=pos(2)  &  yr=pos(3)
ENDIF ELSE BEGIN ;pos
 x0=0.88
 y0=0.10
 xr=0.95
 yr=0.90
 IF keyword_set(hor) THEN BEGIN ;horizontal bar
  x0=0.10 & y0=0.88 &  xr=0.90 &  yr=0.95
 ENDIF ;horizontal bar
ENDELSE ;pos



IF keyword_set(hor) THEN BEGIN 

tv,labelcolor,x0,y0,xsize=(xr-x0),ysize=(yr-y0),/norm
 dy=(yr-y0)/1
 dx=(xr-x0)/n
 FOR i=0,n-1 DO BEGIN ;hor bar
  x(i)=x0+dx*i
  xyouts,x(i)+0.4*dx,y0-0.1*dy,labelname(i),_EXTRA=extra,/norm
 ENDFOR ;hor bar

ENDIF ELSE BEGIN ;vertical default
tv,transpose(labelcolor),x0,y0,xsize=(xr-x0),ysize=(yr-y0),/norm
; write label name
dy=(yr-y0)/n
dx=(xr-x0)/1

 FOR i=0,n-1 DO BEGIN ;vertical bar
  y(i)=y0+dy*i
  xyouts,xr+0.1*dx,y(i)+0.4*dy,labelname(i),_EXTRA=extra,/norm
 ENDFOR ;vertical bar

ENDELSE ;vertical default

return
end