Add an example for scatter plots with auto legends

examples/gallery/plot/scatter.py

@@ -0,0 +1,25 @@
+"""
+Scatter plots with a legend
+---------------------------
+
+TODO: Add more docstrings.
+
+Modified from the matplotlib example: https://matplotlib.org/gallery/lines_bars_and_markers/scatter_with_legend.html
+"""
+
+import numpy as np
+import pygmt
+
+np.random.seed(19680801)
+n = 200  # number of random data points
+
+fig = pygmt.Figure()
+fig.basemap(region=[-0.1, 1.1, -0.1, 1.1], projection='X10c/10c', frame=['xa0.2fg', 'ya0.2fg', 'WSrt'])
+for color in ['blue', 'orange', 'green']:
+    x, y = np.random.rand(2, n)  # random X and Y data in [0,1]
+    sizes = np.random.rand(n) * 0.5  # random size, in cm
+    # plot data points as circles ('c'), with different sizes
+    fig.plot(x, y, style='c', sizes=sizes, color=color, label=f"{color}+S0.25c", t=70)
+
+fig.legend(t=30)
+fig.show()