Cartopy: Lines don't appear when plotting with >1000 points
Description
ax.plot stops showing the line on the axis if there are more than 1000 lat/lon points on a Mercator projection (haven't tried others). The problem doesn't occur if the longitude crosses 0 or I manually transform the points before plotting them.
It might be related to #1240 and #1246, though in this case, lines are desired, not just markers.
Code to reproduce
An example of the problem. Going from 1000 points to 1001 points suddenly prevents the line from showing up.
import cartopy.crs as ccrs
import matplotlib.pyplot as plt
import numpy as np
fig, axes = plt.subplots(1, 2, subplot_kw={'projection': ccrs.Mercator()})
for ax, num_points in zip(axes, [1000, 1001]):
lats = np.linspace(35, 37, num_points)
lons = np.linspace(-117, -115, num_points)
ax.plot(lons, lats, transform=ccrs.PlateCarree())
ax.set_title(f'Number of lat/lon points: {num_points}')
Manually transforming the points prior to plotting fixes the problem.
import cartopy.crs as ccrs
import matplotlib.pyplot as plt
import numpy as np
fig, axes = plt.subplots(1, 2, subplot_kw={'projection': ccrs.Mercator()})
for ax, num_points in zip(axes, [1000, 1001]):
lats = np.linspace(35, 37, num_points)
lons = np.linspace(-117, -115, num_points)
points = ax.projection.transform_points(ccrs.PlateCarree(), lons, lats)
lines2 = ax.plot(points[:, 0], points[:, 1])
ax.set_title(f'Number of lat/lon points: {num_points}')
Traceback
Full environment definition
Operating system
Windows 10
Matplotlib backend: Qt5Agg
Cartopy version
Cartopy 0.17.0 (conda py36h5ae9855_1)
conda list
# packages in environment at C:\anaconda3\envs\pyprop:
#
# Name Version Build Channel
alabaster 0.7.12 py36_0
altgraph 0.16.1 py_0
apipkg 1.5 py36_0
asn1crypto 1.2.0 py36_0
aspy.yaml 1.3.0 py_0 conda-forge
astroid 2.3.3 py36_0
atomicwrites 1.3.0 py36_1
attrs 19.3.0 py_0
autopep8 1.4.4 py_0
babel 2.8.0 py_0
backcall 0.1.0 py36_0
blas 1.0 mkl
ca-certificates 2019.11.27 0
cached-property 1.5.1 py_1
cartopy 0.17.0 py36h5ae9855_1
certifi 2019.11.28 py36_0
cffi 1.13.2 py36h7a1dbc1_0
cfgv 2.0.1 py_0 conda-forge
chardet 3.0.4 py36_1003
cloudpickle 1.2.2 py_0
colorama 0.4.3 py_0
construct 2.9.45 py_0 conda-forge
coverage 5.0 py36he774522_0
cryptography 2.8 py36h7a1dbc1_0
cycler 0.10.0 py36h009560c_0
cython 0.29.14 py36ha925a31_0
decorator 4.4.1 py_0
docutils 0.15.2 py36_0
editdistance 0.5.3 py36h6538335_0 conda-forge
entrypoints 0.3 py36_0
execnet 1.7.1 py_0
flake8 3.7.9 py36_0
freetype 2.9.1 ha9979f8_1
future 0.18.2 py36_0
geos 3.7.1 h33f27b4_0
icc_rt 2019.0.0 h0cc432a_1
icu 58.2 ha66f8fd_1
identify 1.4.9 py_0 conda-forge
idna 2.8 py36_0
imagesize 1.2.0 py_0
importlib_metadata 1.3.0 py36_0
importlib_resources 1.0.2 py36_1000 conda-forge
intel-openmp 2019.4 245
ipykernel 5.1.3 py36h39e3cac_0
ipython 7.11.1 py36h39e3cac_0
ipython_genutils 0.2.0 py36_0
isort 4.3.21 py36_0
jedi 0.15.2 py36_0
jinja2 2.10.3 py_0
joblib 0.14.1 py_0
jpeg 9b hb83a4c4_2
jupyter_client 5.3.4 py36_0
jupyter_core 4.6.1 py36_0
kiwisolver 1.1.0 py36ha925a31_0
lazy-object-proxy 1.4.3 py36he774522_0
libiconv 1.15 h1df5818_7
libpng 1.6.37 h2a8f88b_0
libsodium 1.0.16 h9d3ae62_0
libtiff 4.1.0 h56a325e_0
libxml2 2.9.9 h464c3ec_0
libxslt 1.1.33 h579f668_0
lxml 4.4.2 py36h1350720_0
macholib 1.11 py_0
markupsafe 1.1.1 py36he774522_0
matplotlib 3.1.1 py36hc8f65d3_0
mccabe 0.6.1 py36_1
mkl 2019.4 245
mkl-service 2.3.0 py36hb782905_0
mkl_fft 1.0.15 py36h14836fe_0
mkl_random 1.1.0 py36h675688f_0
more-itertools 8.0.2 py_0
nodeenv 1.3.4 py_0 conda-forge
numpy 1.17.4 py36h4320e6b_0
numpy-base 1.17.4 py36hc3f5095_0
olefile 0.46 py36_0
openssl 1.1.1d he774522_3
owslib 0.18.0 py_0
packaging 20.0 py_0
pandas 0.25.3 py36ha925a31_0
parso 0.5.2 py_0
pefile 2019.4.18 py_0
pickleshare 0.7.5 py36_0
pillow 7.0.0 py36hcc1f983_0
pip 19.3.1 py36_0
pluggy 0.13.1 py36_0
pre-commit 1.21.0 py36_0 conda-forge
proj4 5.2.0 ha925a31_1
prompt_toolkit 3.0.2 py_0
py 1.8.1 py_0
py-cpuinfo 5.0.0 py_0
pycodestyle 2.5.0 py36_0
pycparser 2.19 py36_0
pycrypto 2.6.1 py36hfa6e2cd_9
pyepsg 0.4.0 py36_0
pyflakes 2.1.1 py36_0
pygments 2.5.2 py_0
pyinstaller 3.4 py36h2a8f88b_1
pykdtree 1.3.1 py36h8c2d366_2
pylint 2.4.4 py36_0
pyopenssl 19.1.0 py36_0
pyparsing 2.4.6 py_0
pyproj 1.9.6 py36h6782396_0
pyqt 5.9.2 py36h6538335_2
pyshp 2.1.0 py_0
pysocks 1.7.1 py36_0
pytest 5.3.2 py36_0
pytest-benchmark 3.2.2 py36_0
pytest-cov 2.8.1 py_0
pytest-flake8 1.0.4 py36_0 conda-forge
pytest-forked 1.1.3 py_0
pytest-pylint 0.14.1 py_0 conda-forge
pytest-runner 5.2 py_0
pytest-xdist 1.30.0 py_0
python 3.6.10 h9f7ef89_0
python-dateutil 2.8.1 py_0
python-pptx 0.6.18 py_0 conda-forge
pytz 2019.3 py_0
pywin32 227 py36he774522_0
pywin32-ctypes 0.2.0 py36_0
pyyaml 5.2 py36he774522_0
pyzmq 18.1.0 py36ha925a31_0
qt 5.9.7 vc14h73c81de_0
requests 2.22.0 py36_1
scikit-learn 0.22.1 py36h6288b17_0
scipy 1.3.2 py36h29ff71c_0
setuptools 44.0.0 py36_0
shapely 1.6.4 py36h222a598_0
simplekml 1.3.1 pypi_0 pypi
sip 4.19.8 py36h6538335_0
six 1.13.0 py36_0
snowballstemmer 2.0.0 py_0
sphinx 2.3.1 py_0
sphinxcontrib-applehelp 1.0.1 py_0
sphinxcontrib-devhelp 1.0.1 py_0
sphinxcontrib-htmlhelp 1.0.2 py_0
sphinxcontrib-jsmath 1.0.1 py_0
sphinxcontrib-qthelp 1.0.2 py_0
sphinxcontrib-serializinghtml 1.1.3 py_0
spyder-kernels 1.8.1 py36_0
sqlite 3.30.1 he774522_0
tk 8.6.8 hfa6e2cd_0
toml 0.10.0 py36h28b3542_0
tornado 6.0.3 py36he774522_0
tox 2.8.1 py36_0 conda-forge
tqdm 4.40.2 py_0
traitlets 4.3.3 py36_0
typed-ast 1.4.0 py36he774522_0
urllib3 1.25.7 py36_0
vc 14.1 h0510ff6_4
virtualenv 16.7.5 py_0
vs2015_runtime 14.16.27012 hf0eaf9b_1
wcwidth 0.1.7 py36_0
wheel 0.33.6 py36_0
win_inet_pton 1.1.0 py36_0
wincertstore 0.2 py36h7fe50ca_0
wrapt 1.11.2 py36he774522_0
xlsxwriter 1.2.7 py_0
xz 5.2.4 h2fa13f4_4
yaml 0.1.7 hc54c509_2
yapf 0.28.0 py_0
zeromq 4.3.1 h33f27b4_3
zipp 0.6.0 py_0
zlib 1.2.11 h62dcd97_3
zstd 1.3.7 h508b16e_0
pip list
Package Version Location
----------------------------- ------------------- ------------------------------------------------------------------
alabaster 0.7.12
altgraph 0.16.1
apipkg 1.5
asn1crypto 1.2.0
aspy.yaml 1.3.0
astroid 2.3.3
atomicwrites 1.3.0
attrs 19.3.0
autopep8 1.4.4
Babel 2.8.0
backcall 0.1.0
cached-property 1.5.1
Cartopy 0.17.0
certifi 2019.11.28
cffi 1.13.2
cfgv 2.0.1
chardet 3.0.4
cloudpickle 1.2.2
colorama 0.4.3
construct 2.9.45
coverage 5.0
cryptography 2.8
cycler 0.10.0
Cython 0.29.14
decorator 4.4.1
docutils 0.15.2
editdistance 0.5.3
entrypoints 0.3
execnet 1.7.1
flake8 3.7.9
future 0.18.2
identify 1.4.9
idna 2.8
imagesize 1.2.0
importlib-metadata 1.3.0
importlib-resources 1.0.2
ipykernel 5.1.3
ipython 7.11.1
ipython-genutils 0.2.0
isort 4.3.21
jedi 0.15.2
Jinja2 2.10.3
joblib 0.14.1
jupyter-client 5.3.4
jupyter-core 4.6.1
kiwisolver 1.1.0
lazy-object-proxy 1.4.3
lxml 4.4.2
macholib 1.11
MarkupSafe 1.1.1
matplotlib 3.1.1
mccabe 0.6.1
mkl-fft 1.0.15
mkl-random 1.1.0
mkl-service 2.3.0
more-itertools 8.0.2
nodeenv 1.3.4
numpy 1.17.4
olefile 0.46
OWSLib 0.18.0
packaging 20.0
pandas 0.25.3
parso 0.5.2
pefile 2019.4.18
pickleshare 0.7.5
Pillow 7.0.0
pip 19.3.1
pluggy 0.13.1
pre-commit 1.21.0
prompt-toolkit 3.0.2
py 1.8.1
py-cpuinfo 5.0.0
pycodestyle 2.5.0
pycparser 2.19
pycrypto 2.6.1
pyepsg 0.4.0
pyflakes 2.1.1
Pygments 2.5.2
PyInstaller 3.4
pykdtree 1.3.1
pylint 2.4.4
pyOpenSSL 19.1.0
pyparsing 2.4.6
pyproj 1.9.6
pyshp 2.1.0
PySocks 1.7.1
pytest 5.3.2
pytest-benchmark 3.2.2
pytest-cov 2.8.1
pytest-flake8 1.0.4
pytest-forked 1.1.3
pytest-pylint 0.14.1
pytest-runner 5.2
pytest-xdist 1.30.0
python-dateutil 2.8.1
python-pptx 0.6.18
pytz 2019.3
pywin32 227
pywin32-ctypes 0.2.0
PyYAML 5.2
pyzmq 18.1.0
requests 2.22.0
scikit-learn 0.22.1
scipy 1.3.2
setuptools 44.0.0.post20200106
Shapely 1.6.4.post1
simplekml 1.3.1
six 1.13.0
snowballstemmer 2.0.0
Sphinx 2.3.1
sphinxcontrib-applehelp 1.0.1
sphinxcontrib-devhelp 1.0.1
sphinxcontrib-htmlhelp 1.0.2
sphinxcontrib-jsmath 1.0.1
sphinxcontrib-qthelp 1.0.2
sphinxcontrib-serializinghtml 1.1.3
spyder-kernels 1.8.1
toml 0.10.0
tornado 6.0.3
tox 2.8.1
tqdm 4.40.2
traitlets 4.3.3
typed-ast 1.4.0
urllib3 1.25.7
virtualenv 16.7.5
wcwidth 0.1.7
wheel 0.33.6
win-inet-pton 1.1.0
wincertstore 0.2
wrapt 1.11.2
XlsxWriter 1.2.7
yapf 0.28.0
zipp 0.6.0
dantonacci
All 3 comments
1000 seems to be a very suspiciously round number, but I don't see anything that seems to mention it.
QuLogic
on 8 Feb 2020
Related to an issue I opened last year: https://github.com/SciTools/cartopy/issues/1357
sagrawal-idrc
on 11 May 2020
So the root problem is that given the data here (things in order and > 1000 points) we're triggering an optimization in matplotlib for lines--on that doesn't work for us since our transforms are not generally rectilinear. The fix is to set the axes name to something other than 'rectilinear'. That should also give a workaround for any who need it, just:
ax.name = 'cartopy'
I'll send in a PR in a second.
dopplershift
on 21 Jul 2020
👍3
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Most helpful comment
So the root problem is that given the data here (things in order and > 1000 points) we're triggering an optimization in matplotlib for lines--on that doesn't work for us since our transforms are not generally rectilinear. The fix is to set the axes name to something other than 'rectilinear'. That should also give a workaround for any who need it, just:
I'll send in a PR in a second.