I used to use shapely to make a cirle and plot it on a previously populated plot. This used to work perfectly fine. Recently, I am getting an index error. I broke my code to even the simplest of operations and it cant even do the simplest of circles.
import descartes
import shapely.geometry as sg
import matplotlib.pyplot as plt
circle = sg.Point((0,0)).buffer(1)
# Plot the cricle
fig = plt.figure()
ax = fig.add_subplot(111)
patch = descartes.PolygonPatch(circle)
ax.add_patch(patch)
plt.show()
Below is the error I am getting now. I feel it might be a new version mismatch of something that could have happened. I tried uninstalling and re-installing the last known stable version and that didnt help either
---------------------------------------------------------------------------
IndexError Traceback (most recent call last)
Cell In[20], line 6
4 fig = plt.figure()
5 ax = fig.add_subplot(111)
----> 6 patch = descartes.PolygonPatch(circle)
7 ax.add_patch(patch)
8 plt.show()
File ~/env/lib/python3.8/site-packages/descartes/patch.py:87, in PolygonPatch(polygon, **kwargs)
73 def PolygonPatch(polygon, **kwargs):
74 """Constructs a matplotlib patch from a geometric object
75
76 The `polygon` may be a Shapely or GeoJSON-like object with or without holes.
(...)
85
86 """
---> 87 return PathPatch(PolygonPath(polygon), **kwargs)
File ~/env/lib/python3.8/site-packages/descartes/patch.py:62, in PolygonPath(polygon)
58 else:
59 raise ValueError(
60 "A polygon or multi-polygon representation is required")
---> 62 vertices = concatenate([
63 concatenate([asarray(t.exterior)[:, :2]] +
64 [asarray(r)[:, :2] for r in t.interiors])
65 for t in polygon])
66 codes = concatenate([
67 concatenate([coding(t.exterior)] +
68 [coding(r) for r in t.interiors]) for t in polygon])
70 return Path(vertices, codes)
File ~/env/lib/python3.8/site-packages/descartes/patch.py:63, in <listcomp>(.0)
58 else:
59 raise ValueError(
60 "A polygon or multi-polygon representation is required")
62 vertices = concatenate([
---> 63 concatenate([asarray(t.exterior)[:, :2]] +
64 [asarray(r)[:, :2] for r in t.interiors])
65 for t in polygon])
66 codes = concatenate([
67 concatenate([coding(t.exterior)] +
68 [coding(r) for r in t.interiors]) for t in polygon])
70 return Path(vertices, codes)
IndexError: too many indices for array: array is 0-dimensional, but 2 were indexed
So from what I could tell, this issue comes from a broken implementation of shapely within descartes.
My speculation is that shapely changed how it handles Polygon exteriors and descartes simply hasn't been updated.
I don't know if it is the best idea, but I edited my installation of descartes directly to fix this issue:
Navigate to your descartes installation and open patch.py.
At line 62 you should see this piece of code:
vertices = concatenate([
concatenate([asarray(t.exterior)[:, :2]] + [asarray(r)[:, :2] for r in t.interiors])
for t in polygon])
Simply change t.exterior to t.exterior.coords. This hopefully should fix your issue.
vertices = concatenate([
concatenate([asarray(t.exterior.coords)[:, :2]] + [asarray(r)[:, :2] for r in t.interiors])
for t in polygon])
I'm trying to find a way to provide the descartes devs with this feedback.