Note
Click here to download the full example code
Configuring PyGMT defaults¶
Default GMT parameters can be set globally or locally using pygmt.config
.
import pygmt
Configuring default GMT parameters¶
Users can override default parameters either temporarily (locally) or permanently
(globally) using pygmt.config
. The full list of default parameters that can be
changed can be found at https://docs.generic-mapping-tools.org/latest/gmt.conf.html.
We demonstrate the usage of pygmt.config
by configuring a map plot.
# Start with a basic figure with the default style
fig = pygmt.Figure()
fig.basemap(region=[115, 119.5, 4, 7.5], projection="M10c", frame=True)
fig.coast(land="black", water="skyblue")
fig.show()
Out:
<IPython.core.display.Image object>
Globally overriding defaults¶
The MAP_FRAME_TYPE
parameter specifies the style of map frame to use, of which there
are 5 options: fancy
(default, seen above), fancy+
, plain
, graph
(which does not apply to geographical maps) and inside
.
The FORMAT_GEO_MAP
parameter controls the format of geographical tick annotations.
The default uses degrees and minutes. Here we specify the ticks to be a decimal number
of degrees.
fig = pygmt.Figure()
# Configuration for the 'current figure'.
pygmt.config(MAP_FRAME_TYPE="plain")
pygmt.config(FORMAT_GEO_MAP="ddd.xx")
fig.basemap(region=[115, 119.5, 4, 7.5], projection="M10c", frame=True)
fig.coast(land="black", water="skyblue")
fig.show()
Out:
<IPython.core.display.Image object>
Locally overriding defaults¶
It is also possible to temporarily override the default parameters, which is very
useful for limiting the scope of changes to a particular plot. pygmt.config
is
implemented as a context manager, which handles the setup and teardown of a GMT
session. Python users are likely familiar with the with open(...) as file:
snippet,
which returns a file
context manager. In this way, it can be used to override a parameter
for a single command, or a sequence of commands. An application of pygmt.config
as a context manager is shown below:
fig = pygmt.Figure()
# This will have a fancy+ frame
with pygmt.config(MAP_FRAME_TYPE="fancy+"):
fig.basemap(region=[115, 119.5, 4, 7.5], projection="M10c", frame=True)
fig.coast(land="black", water="skyblue")
# Shift plot origin down by 10cm to plot another map
fig.shift_origin(yshift="-10c")
# This figure retains the default "fancy" frame
fig.basemap(region=[115, 119.5, 4, 7.5], projection="M10c", frame=True)
fig.coast(land="black", water="skyblue")
fig.show()
Out:
<IPython.core.display.Image object>
Total running time of the script: ( 0 minutes 1.917 seconds)