Notebook to check that all rivers are separate, not on top of each other
from salishsea_tools import river_201803 as rivers
all_points = []
for region in rivers.prop_dict:
for river in rivers.prop_dict[region]:
ii = rivers.prop_dict[region][river]['i']
jj = rivers.prop_dict[region][river]['j']
all_points += [(ii, jj)]
len(all_points) == len(set(all_points))
True