Coastlines and borders

Plotting coastlines and borders is handled by pygmt.Figure.coast.

import pygmt

Shorelines

Use the shorelines parameter to plot only the shorelines:

fig = pygmt.Figure()
fig.basemap(region="g", projection="W15c", frame=True)
fig.coast(shorelines=True)
fig.show()

The shorelines are divided in 4 levels:

1. coastline

2. lakeshore

3. island-in-lake shore

4. lake-in-island-in-lake shore

You can specify which level you want to plot by passing the level number and a GMT pen configuration. For example, to plot just the coastlines with 0.5p thickness and black lines:

fig = pygmt.Figure()
fig.basemap(region="g", projection="W15c", frame=True)
fig.coast(shorelines="1/0.5p,black")
fig.show()

You can specify multiple levels (with their own pens) by passing a list to shorelines:

fig = pygmt.Figure()
fig.basemap(region="g", projection="W15c", frame=True)
fig.coast(shorelines=["1/1p,black", "2/0.5p,red"])
fig.show()

Resolutions

The coastline database comes with 5 resolutions: "full", "high", "intermediate", "low", and "crude". The resolution drops by 80% between levels. The resolution parameter defaults to "auto" to automatically select the best resolution given the chosen map scale.

oahu = [-158.3, -157.6, 21.2, 21.8]
fig = pygmt.Figure()
for res in ["crude", "low", "intermediate", "high", "full"]:
    fig.coast(resolution=res, shorelines="1p", region=oahu, projection="M5c")
    fig.shift_origin(xshift="5c")
fig.show()

Land and water

Use the land and water parameters to specify a fill color for land and water bodies. The colors can be given by name or hex codes (like the ones used in HTML and CSS):

fig = pygmt.Figure()
fig.basemap(region="g", projection="W15c", frame=True)
fig.coast(land="#666666", water="skyblue")
fig.show()