PRO coordinate_grid,X,Y,N,M,CENTER=center,TYPE=type
;+
;coordinate_grid,X,Y,N,M makes a grid of (x,y) coordinates of size NxM,
;where N is the number of columns and M is the number of rows.
;
;coordinate_grid,X,Y,N,M,/CENTER produces X and Y with (0,0) at position
;(N/2,M/2).
;
;H. Rhody
;October 31, 2002
;-

IF N_Elements(type) LE 0 THEN type=2
IF KEYWORD_SET(center) THEN BEGIN
	xshift=N/2 & yshift=M/2
	ENDIF ELSE BEGIN
	xshift=0 & yshift=0
	ENDELSE
X=(Make_Array(N,/INDEX,TYPE=type)-xshift)#Replicate(1,M)
Y=(Make_Array(M,/INDEX,TYPE=type)-yshift)##Replicate(1,N)

RETURN
END