How to troubleshoot installation issues?

There are three installation processes:

the Anaconda way (recommended), the most simple way, with only one command to execute;
```
conda create -n traffic -c conda-forge python=3.9 traffic
```
the pip way, but you are responsible for non Python dependency management. With Linux, you may check how the environment is created for GitHub Actions;
```
pip install traffic
```
the poetry way, recommended for development, which ensures the same versions of all dependencies are installed in a virtual environment on any computer running the library: this step is crucial for consistency in continuous integration.
```
poetry install
```

The following questions are the most common about installation issues:

Installation is really slow, conda stalls on the resolution process

Before filing a bug report, please try again:
- to start the installation from a fresh conda environment, please do not reuse a potentially corrupted environment (when conda loses track of dependency versions);
- to disable the channel_priority option with
```
conda config --set channel_priority disabled
```
If you cannot see the end of the tunnel, consider running traffic with the provided Dockerfile.
Python crashes when I try to reproduce plots in the documentation

Usually, this happens when there is something wrong with your Cartopy and/or shapely installation. These libraries strongly depend on the geos and proj libraries. You must have shapely and Cartopy versions matching the correct versions of these libraries.

The problem is sometimes hard to understand, and you may end up fixing it without really knowing how.

If you don’t know how to install these dependencies, start with a fresh Anaconda distribution and install the following libraries the conda way:
```
conda install cartopy shapely
```
If it still does not work, try something along:
```
conda uninstall cartopy shapely
pip uninstall cartopy shapely
# be sure to remove all previous versions before installing again
conda install cartopy shapely
```
If it still does not work, try again with:
```
conda uninstall cartopy shapely
pip uninstall cartopy shapely
# this forces the recompilation of the packages
pip install --no-binary :all: cartopy shapely
```

Widgets do not display in Jupyter Lab or Jupyter Notebook

After executing a cell in a Jupyter environment, you may see one of the following output:

A Jupyter Widget
# or
Error displaying widget
# or
HBox(children=(IntProgress(value=0, max=1), HTML(value='')))
# or
Map(basemap={'url': 'https://{s}.tile.openstreetmap.org/…

You will need to activate the widgets extensions:

with Jupyter Lab:

jupyter labextension install @jupyter-widgets/jupyterlab-manager
jupyter labextension install jupyter-leaflet

with Jupyter Notebook:

jupyter nbextension enable --py --sys-prefix widgetsnbextension
jupyter nbextension enable --py --sys-prefix ipyleaflet