pro s_vol_surf xd=600 yd=600 xwind=xd ywind=yd ximag=xd yimag=yd openr,2,'vol_surf.byt' q=assoc(2,bytarr(ximag,yimag)) window,2,xsize=xwind,ysize=ywind,xpos=250,ypos=130 loadct,1 tvscl,q(0) close,2 end