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Open a shapefile using Fiona, and plot its features using Matplotlib and Descartes
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import matplotlib.pyplot as plt | |
from matplotlib.collections import PatchCollection | |
from descartes import PolygonPatch | |
import fiona | |
from shapely.geometry import Polygon, MultiPolygon, shape | |
# We can extract the London Borough boundaries by filtering on the AREA_CODE key | |
mp = MultiPolygon( | |
[shape(pol['geometry']) for pol in fiona.open('data/boroughs/boroughs.shp') | |
if pol['properties']['AREA_CODE'] == 'LBO']) | |
# We can now do GIS-ish operations on each borough polygon! | |
# we could randomize this by dumping the polygons into a list and shuffling it | |
# or we could define a random colour using fc=np.random.rand(3,) | |
# available colour maps are here: http://wiki.scipy.org/Cookbook/Matplotlib/Show_colormaps | |
cm = plt.get_cmap('RdBu') | |
num_colours = len(mp) | |
fig = plt.figure() | |
ax = fig.add_subplot(111) | |
minx, miny, maxx, maxy = mp.bounds | |
w, h = maxx - minx, maxy - miny | |
ax.set_xlim(minx - 0.2 * w, maxx + 0.2 * w) | |
ax.set_ylim(miny - 0.2 * h, maxy + 0.2 * h) | |
ax.set_aspect(1) | |
patches = [] | |
for idx, p in enumerate(mp): | |
colour = cm(1. * idx / num_colours) | |
patches.append(PolygonPatch(p, fc=colour, ec='#555555', alpha=1., zorder=1)) | |
ax.add_collection(PatchCollection(patches, match_original=True)) | |
ax.set_xticks([]) | |
ax.set_yticks([]) | |
plt.title("Shapefile polygons rendered using Shapely") | |
plt.savefig('data/london_from_shp.png', alpha=True, dpi=300) | |
plt.show() |
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