Contouring onto a map and writing to .png

There was something missing from that last plot -- where in world is the plot of? It's usually fairly easy to use maps in IDL.

 
pos=[0.15,0.15,0.9,0.8]
map_set,/mercator , limit=[0,-30,40,40],position=pos
map_continents, limit=[0,-30,40,40],position=pos
wvmr_levs=indgen(21)*2.-10
contour,q(*,*,20,0)*1000.,lon,lat,levels=wvmr_levs,/fill,/overplot
map_continents, limit=[0,-30,40,40],position=pos,thick=3

t_levs=indgen(25)*5.+270.
contour,t(*,*,20,0),lon,lat,/overplot,levels=t_levs,c_labels=t_levs*0.+1

contour,wvmr_levs#(intarr(11)+1),wvmr_levs,indgen(11),position=[0.15,0.88,0.9,0.93],levels=wvmr_levs,xrange=[0,20],/fill,/noerase,ystyle=4,title='WVMR (gkg!E-1!N)',xstyle=1
contour,wvmr_levs#(intarr(11)+1),wvmr_levs,indgen(11),levels=wvmr_levs,ystyle=4,/overplot

Writing to a .png graphics file is easy

 
write_png,'~lecjm/test_png_out.png',tvrd()