use get_legend_arg_names function in create_empty_legend
use get_legend_arg_names function in create_empty_legend

jread-usgs/gsplot,ldecicco-USGS/gsplot,lindsaycarr/gsplot,ldecicco-USGS/gsplot,jread-usgs/gsplot,dpattermann-usgs/gsplot,lindsaycarr/gsplot,dpattermann-usgs/gsplot,USGS-R/gsplot