Coastlines and borders

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

import pygmt

Shorelines

Use the shorelines argument to plot only the shorelines:

fig = pygmt.Figure()
fig.basemap(region="g", projection="W10i", frame=True)
fig.coast(shorelines=True)
fig.show()

Out:

<IPython.core.display.Image object>

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 0.5 thickness and black lines:

fig = pygmt.Figure()
fig.basemap(region="g", projection="W10i", frame=True)
fig.coast(shorelines="1/0.5p,black")
fig.show()

Out:

<IPython.core.display.Image object>

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

fig = pygmt.Figure()
fig.basemap(region="g", projection="W10i", frame=True)
fig.coast(shorelines=["1/1p,black", "2/0.5p,red"])
fig.show()

Out:

<IPython.core.display.Image object>

Resolutions

The coastline database comes with 5 resolutions. The resolution drops by 80% between levels:

1. "c": crude

2. "l": low (default)

3. "i": intermediate

4. "h": high

5. "f": full

oahu = [-158.3, -157.6, 21.2, 21.8]
fig = pygmt.Figure()
for res in ["c", "l", "i", "h", "f"]:
    fig.coast(resolution=res, shorelines="1p", region=oahu, projection="M5i")
    fig.shift_origin(xshift="5i")
fig.show()

Out:

<IPython.core.display.Image object>

Land and water

Use the land and water attributes 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="W10i", frame=True)
fig.coast(land="#666666", water="skyblue")
fig.show()

Out:

<IPython.core.display.Image object>