Using Features Offline

Creating Environment

Under the hood, GeoViews features simply wrap cartopy features, so it’s a matter of properly configuring cartopy ahead of time.

1. Create a new cartopy environment (or use an existing one):

   conda create -n cartopy_env python=3.10
   

2. Install the required packages (note that cartopy_offlinedata is about 200MBs):

   conda install -c conda-forge geoviews cartopy cartopy_offlinedata
   

   Or if you have an environment already, you may just need cartopy_offlinedata:

   conda install -c conda-forge cartopy_offlinedata
   

Verifying Setup

Now, we will verify that the shapefiles are available offline.

1. Ensure offline shapefiles were downloaded:

   from pathlib import Path
   import cartopy
   
   data_dir = Path(cartopy.config["pre_existing_data_dir"])
   shapefiles = data_dir / "shapefiles" / "natural_earth" / "cultural"
   list(shapefiles.glob("*"))
   

2. Test GeoViews offline (toggle internet off):

   import geoviews as gv
   from bokeh.resources import INLINE
   
   gv.extension("bokeh")
   
   coastline = gv.feature.coastline()
   borders = gv.feature.borders()
   world = (coastline * borders).opts(global_extent=True)
   
   gv.save(world, "world.html", resources=INLINE)
   

   Please ensure to set resources=INLINE if the machine you’re using is completely offline and you intend to view the output on that machine. Failure to do so will result in the HTML file appearing empty when opened.

Changing Directory

If you wish to change the default data directory, follow these steps.

1. Create a new directory and move the data:

   from pathlib import Path
   import cartopy
   
   new_data_dir = Path("~/.cartopy").expanduser()
   new_data_dir.mkdir(exist_ok=True)
   
   data_dir = Path(cartopy.config["pre_existing_data_dir"])
   data_dir.rename(new_data_dir / "cartopy")
   

2. Point to the new data directory within the script:

   from pathlib import Path
   
   import cartopy
   import geoviews as gv
   from bokeh.resources import INLINE
   
   cartopy.config["pre_existing_data_dir"] = str(Path("~/.cartopy/cartopy").expanduser())
   
   gv.extension("bokeh")
   
   coastline = gv.feature.coastline()
   borders = gv.feature.borders()
   world = (coastline * borders).opts(global_extent=True)
   
   gv.save(world, "world.html", resources=INLINE)
   

3. Or set an environment variable CARTOPY_DATA_DIR:

   For sh:

   export CARTOPY_DATA_DIR="$HOME/.cartopy/cartopy"
   

   For powershell:

   $env:CARTOPY_DATA_DIR = "$HOME/.cartopy/cartopy"
   

   For cmd:

   set CARTOPY_DATA_DIR=%USERPROFILE%\.cartopy\cartopy
   

   Please note using tilde (~) in the environment variable will not work.