More advanced example
From CrewWiki
o=obj_new('cws_read',xrange=[1500,2800],yrange=[2800,3400],scale=0.3)
ls = o->land_sea()
coast=o->coast_line(/vector)
o->set_product,'ctp'
o->set_group,'AWG'
ctp1=o->get_data()
view2d,ctp1,/cool,/colo,no_data_idx=where(ctp1 le 0),coast_vec=coast,title='EUM ctp', min=200
longitude=o->lon()
latitude =o->lat()
rgb = o->rgb() & view2d,rgb,/cool,/no_axes
o->set_date,2008,6,13,12,0
o->set_group,'GSF'
ctp2=o->get_data()
view2d,ctp2,/cool,/colo,no_data_idx=where(ctp2 le 0),coast_vec=coast,title='GSF ctp',min=200
view2d,array-ctp2,/cool,/colo,no_data_idx=where((ctp1 le 0) or (ctp2 le 0) or (abs(ctp1-ctp2) gt 150)),coast_vec=coast,title='difference ctp AWG-GSF',min=-150,max=150
obj_destroy, o