tricontour and tricontourf produce wrong bounds

[MiCurry]

Description

Similar to issue #811 and its fix #814, tricontour and tricountourf incorrectly
Change the bounds of the plot to be extremely zoomed in. i.e.:

The extent can be reset using:

ax.relim()
ax.autoscale_view()

Code to reproduce

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
import cartopy.crs as ccrs

npts = 5000
latCell = np.random.uniform(-90.0, 90.0, npts)
lonCell = np.random.uniform(-180.0, 180.0, npts)
data = np.random.random_sample((latCell.shape[0]))

bmap = ccrs.Orthographic()

ax = plt.axes(projection=bmap)

ax.coastlines()
ax.gridlines()

plt.tricontourf(lonCell, 
                latCell, 
                data,
                75,
                vmin=data.min(),
                vmax=data.max(),
                transform=ccrs.PlateCarree())

#ax.relim()
#ax.autoscale_view()

Similar open issues include #1301, #1302 and maybe #1293(?). We definitely have some interest in getting tricontour and tricontourf working correctly for plotting MPAS field. I definitely have an interesting in helping make this contribution, but I'll need to get permission from NCAR and I would most likely need some help making the change as well.

Full environment definition

Operating system

SUSE Linux Enterprise Server 12 SP4

Cartopy version

0.17.0

conda list

Not using conda

pip list

 Package                       Version    Location                        
----------------------------- ---------- --------------------------------
alabaster                     0.7.12     
ASAPTools                     0.6.2      
asn1crypto                    0.24.0     
aspy.yaml                     1.3.0      
astroid                       2.2.5      
atomicwrites                  1.3.0      
attrs                         19.1.0     
Babel                         2.7.0      
backcall                      0.1.0      
basemap                       1.2.0      
bash-kernel                   0.7.1      
beautifulsoup4                4.7.1      
bitstring                     3.1.5      
bleach                        3.1.0      
boto3                         1.9.179    
botocore                      1.12.179   
Bottleneck                    1.2.1      
Cartopy                       0.17.0     
cdsapi                        0.1.4      
certifi                       2019.6.16  
cf-units                      2.0.2      
cffi                          1.12.3     
cfgv                          2.0.0      
cftime                        1.0.3.4    
chardet                       3.0.4      
click                         6.7        
click-plugins                 1.1.1      
cligj                         0.5.0      
cloudpickle                   1.2.1      
cmocean                       2.0        
colorspacious                 1.1.2      
configobj                     5.0.6      
coverage                      4.5.3      
cryptography                  2.5        
cycler                        0.10.0     
Cython                        0.29.10    
dask                          2.0.0      
dask-jobqueue                 0.5.0      
decorator                     4.4.0      
dedalus                       2.1810     
defusedxml                    0.6.0      
distributed                   2.0.1      
docopt                        0.6.2      
docrep                        0.2.7      
docutils                      0.14       
entrypoints                   0.3        
ESMPy                         7.1.0.dev0 
Fiona                         1.8.4      
GDAL                          2.4.0      
geopandas                     0.5.0      
gfstonc                       0.0.1      
globus-cli                    1.10.1     
globus-sdk                    1.7.1      
h5py                          2.9.0      
HeapDict                      1.0.0      
html5lib                      1.0.1      
httplib2                      0.13.0     
icc-rt                        2019.0     
identify                      1.4.5      
idl-python                    2.0        
idna                          2.8        
imageio                       2.5.0      
imagesize                     1.1.0      
importlib-metadata            0.18       
importlib-resources           1.0.2      
intel-openmp                  2019.0     
ipykernel                     5.1.1      
ipyparallel                   6.2.4      
ipython                       7.5.0      
ipython-genutils              0.2.0      
ipywidgets                    7.4.2      
isort                         4.3.21     
jedi                          0.14.0     
Jinja2                        2.10.1     
jmespath                      0.9.2      
joblib                        0.13.2     
jsonschema                    3.0.1      
jupyter                       1.0.0      
jupyter-client                5.2.4      
jupyter-console               6.0.0      
jupyter-core                  4.5.0      
jupyterlab                    0.35.6     
jupyterlab-server             0.2.0      
kiwisolver                    1.1.0      
lazy-object-proxy             1.4.1      
llvmlite                      0.27.0     
MarkupSafe                    1.1.1      
matlab-kernel                 0.16.7     
matlabengineforpython         R2018a     
matplotlib                    2.2.3      
mccabe                        0.6.1      
metakernel                    0.24.2     
MetPy                         0.10.0     
mistune                       0.8.4      
mkl                           2019.0     
mkl-fft                       1.0.6      
mkl-random                    1.0.1.1    
more-itertools                7.1.0      
MPAS-Limited-Area             0.1
mpi4py                        3.0.0      
msgpack                       0.6.1      
munch                         2.3.2      
natgrid                       0.2.1      
nbconvert                     5.5.0      
nbformat                      4.4.0      
netCDF4                       1.5.1.2    
networkx                      2.3        
ngl                           1.6.1      
nodeenv                       1.3.3      
nose                          1.3.7      
nose2                         0.9.1      
notebook                      5.7.8      
numba                         0.42.0     
numexpr                       2.6.9      
numpy                         1.15.4     
ocgis                         2.1.1      
olefile                       0.46       
packaging                     19.0       
pandas                        0.24.2     
pandocfilters                 1.4.2      
parse                         1.12.0     
parso                         0.5.0      
pexpect                       4.7.0      
pickleshare                   0.7.5      
Pillow                        6.0.0      
Pint                          0.9        
pip                           19.1.1     
pluggy                        0.12.0     
pooch                         0.2.1      
pre-commit                    1.17.0     
prettytable                   0.7.2      
progressbar2                  3.42.0     
prometheus-client             0.7.1      
prompt-toolkit                2.0.9      
protobuf                      3.9.0rc1   
psutil                        5.6.3      
ptyprocess                    0.6.0      
py                            1.8.0      
pybufrkit                     0.2.7      
pycparser                     2.19       
Pydap                         3.2.2      
Pygments                      2.4.2      
pygraphviz                    1.5        
pygrib                        2.0.3      
pyhdf                         0.9.0      
PyJWT                         1.7.1      
pylint                        2.3.1      
PyNIO                         1.5.5      
pyparsing                     2.4.0      
pyproj                        1.9.6      
pyrsistent                    0.15.2     
pyshp                         2.1.0      
pyspharm                      1.0.8      
pytest                        4.6.3      
python-dateutil               2.8.0      
python-utils                  2.3.0      
pytz                          2019.1     
PyWavelets                    1.0.3      
PyYAML                        5.1.1      
pyzmq                         18.0.2     
qtconsole                     4.5.1      
regionmask                    0.4.0      
requests                      2.22.0     
rise                          5.5.0      
s3transfer                    0.2.1      
scikit-image                  0.15.0     
scikit-learn                  0.21.2     
scipy                         1.3.0      
seaborn                       0.9.0      
Send2Trash                    1.5.0      
setuptools                    41.0.1     
sh                            1.12.14    
Shapely                       1.7a1      
SHTns                         3.1        
sip                           4.19.13    
siphon                        0.8.0      
six                           1.12.0     
SkewT                         1.1.0      
sklearn-xarray                0.3.0      
snowballstemmer               1.9.0      
sortedcontainers              2.1.0      
soupsieve                     1.9.2      
Sphinx                        2.1.2      
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      
tables                        3.4.4      
tbb                           2019.0     
tbb4py                        2019.0     
tblib                         1.4.0      
terminado                     0.8.2      
testpath                      0.4.2      
toml                          0.10.0     
toolz                         0.9.0      
tornado                       6.0.3      
traitlets                     4.3.2      
typed-ast                     1.4.0      
urllib3                       1.25.3     
virtualenv                    16.6.1     
virtualenv-clone              0.5.3      
viscm                         0.8        
wcwidth                       0.1.7      
webencodings                  0.5.1      
WebOb                         1.8.5      
wheel                         0.33.4     
widgetsnbextension            3.4.2      
wrapt                         1.11.2     
wrf-python                    1.3.0      
wurlitzer                     1.0.3      
xarray                        0.12.1     
xesmf                         0.1.1      
xlrd                          1.2.0      
zict                          1.0.0      
zipp                          0.5.1      

[MiCurry]

I also noticed this bug when applying a collection of patches to an axes:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.collections as mplcollections
from matplotlib.patches import Circle
import cartopy.crs as ccrs

colors = np.linspace(0, 1, num=4)

bmap = ccrs.Orthographic(central_longitude=-100)

ax = plt.axes(projection=bmap)

ax.coastlines()
ax.gridlines()

patches = [] 
patches.append(Circle((-90, -45), radius=30))
patches.append(Circle((-90, 45), radius=30))

collection = mplcollections.PatchCollection(patches, 
                                            transform=ccrs.PlateCarree())

collection.set_array(colors)
ax.add_collection(collection)

#ax.relim()
#ax.autoscale_view()

And then after ax.relim() and ax.autoscale_view():

Perhaps there is a better method for doing this in Cartopy that I am not aware of?

[koldunovn]

@MiCurry any development on this one?

[greglucas]

This is due to the extent of the axes not being initialized immediately to your coordinate frame. If you add ax.set_global() right after your axis creation this works as you expect I think.

ax = plt.axes(projection=bmap)
ax.set_global()

See PR #1370 for an attempt to clear up this common confusion.

[MiCurry]

@koldunovn It appears so! Thanks for the information and the PR on this @greglucas.