Add gallery example for geopandas point geometry (cities in Europe from Natural Earth) (#4231)

Author: yvonnefroehlich

examples/gallery/symbols/points_cities.py

@@ -0,0 +1,50 @@
+"""
+GeoPandas: Plotting points with Point or MultiPoint geometry
+============================================================
+
+The :meth:`pygmt.Figure.plot` method allows us to plot geographical data such as points
+with Point or MultiPoint geometry types stored in a :class:`geopandas.GeoDataFrame`
+object. Use :func:`geopandas.read_file` to load data from any supported OGR format such
+as a shapefile (.shp), GeoJSON (.geojson), geopackage (.gpkg), etc. Then, pass the
+:class:`geopandas.GeoDataFrame` object as an argument to the ``data`` parameter of
+:meth:`pygmt.Figure.plot`, and style the points using the ``fill`` and ``pen``
+parameters. Additionally, pass suitable columns of the :class:`geopandas.GeoDataFrame`
+to the ``x``,  ``y``, and ``text`` parameters of the :meth:`pygmt.Figure.text` method
+to label specific features.
+"""
+
+# %%
+import geopandas as gpd
+import pygmt
+
+# Read a sample dataset provided by Natural Earth. The dataset contains cities stored
+# as Point geometry type. In this example we focus on Europe.
+provider = "https://naciscdn.org/naturalearth"
+cities = gpd.read_file(f"{provider}/50m/cultural/ne_50m_populated_places_simple.zip")
+cities = cities[cities["name"] != "Vatican City"].copy()  # No overlap with label Rome
+# Create two subsets for small and large cities
+cities_small = cities[cities["worldcity"] != 1].copy()
+cities_large = cities[cities["worldcity"] == 1].copy()
+
+fig = pygmt.Figure()
+fig.basemap(region=[-10, 32.7, 37, 57], projection="M12c", frame=True)
+fig.coast(land="gray95", shorelines="1/0.3p,gray50")
+
+# Plot the two subsets using squares with different sizes and fills.
+fig.plot(data=cities_small, style="s0.1c", fill="lightgray", pen="0.5p")
+fig.plot(data=cities_large, style="s0.15c", fill="darkorange", pen="0.5p")
+
+# Label the larger cities with their names.
+fig.text(
+    x=cities_large.geometry.x,
+    y=cities_large.geometry.y,
+    text=cities_large["name"],
+    offset="0.12c",
+    justify="BL",
+    font="6p,Helvetica-Bold",
+    fill="white@30",
+    pen="0.5p,darkorange",
+    clearance="0.05c+tO",
+)
+
+fig.show()