Add gallery example showing usage of line objects from a geopandas.GeoDataFrame

[michaelgrund]

Description of proposed changes

Here's the first gallery example showcasing how to plot line objects stored in a geopandas.GeoDataFrame (see #1374).

Preview at https://pygmt-git-gallery-gpd-lines-gmt.vercel.app/gallery/maps/roads.html

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

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[weiji14]

Thanks @michaelgrund! This geopandas example will be a nice addition to the gallery 😁

To fix the failing CI docs test, you'll need to add geopandas as a dependency at

pygmt/.github/workflows/ci_docs.yml

Lines 69 to 70 in 16bc8ab

	conda install gmt=6.2.0 numpy pandas xarray netCDF4 packaging \
	ipython make myst-parser \

[michaelgrund]

Thanks @michaelgrund! This geopandas example will be a nice addition to the gallery 😁

To fix the failing CI docs test, you'll need to add geopandas as a dependency at

pygmt/.github/workflows/ci_docs.yml

Lines 69 to 70 in 16bc8ab

	conda install gmt=6.2.0 numpy pandas xarray netCDF4 packaging \
	ipython make myst-parser \

Added in #1481.

[weiji14]

Unrelated test failure due to setuptools_scm v6.3.0 having some error about missing tomli (see pypa/setuptools-scm#608). They've released v6.3.1 so should be all good now, restarting tests.

[weiji14]

Just two more comments from me, otherwise ready for final review. Will give it until the end of the week (Friday 10/9/2021) since it's a public holiday in the US.

[weiji14]

I've figured it out! We can use the octal code for apostrophe (') which is 047, see https://docs.generic-mapping-tools.org/6.2/cookbook/octal-codes.html.

Suggested change

	fig.basemap(
	region=region,
	projection="M12c",
	frame=["af", 'WSne+t"Main roads of Oahu (Hawaii)"'],
	)
	title = r"Main roads of O\047ahu (Hawai\047i)" # \047 is octal code for '
	fig.basemap(region=region, projection="M12c", frame=["af", f'WSne+t"{title}"'])

[michaelgrund]

Great @weiji14!

[weiji14]

Realizing two years later that I used the wrong symbol 😅 It should be an Okina ʻ (U+02BB) instead of an apostrophe. Looks more like a 6 than a 9.

[seisman]

The example looks good to me, but I'm not sure if we should put the example in the "Maps and map elements" or the "Lines and vectors" category.

[michaelgrund]

The example looks good to me, but I'm not sure if we should put the example in the "Maps and map elements" or the "Lines and vectors" category.

Of course, we should definitely discuss that before merging. Would be happy with both categories since the example contains elements that would fit into both.

[willschlitzer]

Looks good to me!

[seisman]

The example looks good to me, but I'm not sure if we should put the example in the "Maps and map elements" or the "Lines and vectors" category.

Of course, we should definitely discuss that before merging. Would be happy with both categories since the example contains elements that would fit into both.

I prefer to have this example in the "Lines and vectors" category, because the example focuses on plotting lines from GeoDataFrame, rather than plotting a map.

[michaelgrund]

I prefer to have this example in the "Lines and vectors" category, because the example focuses on plotting lines from GeoDataFrame, rather than plotting a map.

Done!

[seisman]

Looks good to me.