I wish to produce a set of 32 polygons for each county on the island of Ireland. I found shapefiles here of all 32 counties:


The problem is that there are no lakes and the Shannon Estuary is missing.

I then found lake data here but the lake resolution is low and still no Shannon Estuary:


How might I acquire the required polygons?

Here what I have so far for the code below: enter image description here

from shapely.geometry import Polygon, MultiPolygon, mapping, shape
import fiona
import matplotlib.pyplot as plt
from descartes.patch import PolygonPatch

ireland = Polygon([(-5.34,55.43), (-10.56,55.43), (-10.56,51.39), (-5.34,51.39)])

lakes = []
with fiona.open("./ne_10m_lakes/ne_10m_lakes.shp") as shapes: 
  for s in shapes: lakes.append(shape(s['geometry']))
with fiona.open("./ne_10m_lakes_europe/ne_10m_lakes_europe.shp") as shapes:
  for s in shapes: lakes.append(shape(s['geometry']))
lakes = MultiPolygon([s for s in lakes if s.intersects(ireland)])

counties = {}
with fiona.open("./counties/counties.shp") as shapes:
  for s in shapes:
    assert s['properties']['NAME_EN'][:7] == "County "
    counties[ s['properties']['NAME_EN'][7:] ] = shape(s['geometry'])

# 32 counties
counties = [c.difference(lakes) for c in counties.values()]

fig = plt.figure()
ax = fig.add_subplot(111)

for s in counties:
    p = PolygonPatch(s)


1 Answer 1


I think the issue may be that the political boundaries won't include water and lakes.

Here are some options

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