Inset map showing a rectangle region

The pygmt.Figure.inset method adds an inset figure inside a larger figure. The function is called using a with statement, and its position, box, offset, and margin can be customized. Plotting methods called within the with statement plot into the inset figure.

Out:

<IPython.core.display.Image object>

import numpy as np
import pygmt

# Set the region of the main figure
region = [137.5, 141, 34, 37]

fig = pygmt.Figure()

# Plot the base map of the main figure
fig.basemap(region=region, projection="M12c", frame=["WSne", "af"])

# Set the land color to "lightbrown", the water color to "azure1", the shorelines
# width to "2p", the area threshold to 1000 km^2 for the main figure
fig.coast(land="lightbrown", water="azure1", shorelines="2p", area_thresh=1000)

# Create an inset map, setting the position to bottom right, the width to
# 3 centimeters, the height to 3.6 centimeters, and the x- and y-offsets to
# 0.1 centimeters. Draws a rectangular box around the inset with a fill color
# of "white" and a pen of "1p".
with fig.inset(position="jBR+w3c/3.6c+o0.1c", box="+gwhite+p1p"):
    # Plot the Japan main land in the inset using coast. "M?" means Mercator
    # projection with map width automatically determined from the inset width.
    # Highlight the Japan area in "lightbrown"
    # and draw its outline with a pen of "0.2p".
    fig.coast(
        region=[129, 146, 30, 46],
        projection="M?",
        dcw="JP+glightbrown+p0.2p",
        area_thresh=10000,
    )
    # Plot a rectangle ("r") in the inset map to show the area of the main figure.
    # "+s" means that the first two columns are the longitude and latitude of
    # the bottom left corner of the rectangle, and the last two columns the
    # longitude and latitude of the uppper right corner.
    rectangle = [[region[0], region[2], region[1], region[3]]]
    fig.plot(data=rectangle, style="r+s", pen="2p,blue")

fig.show()