Plotting Date Time Charts

Plotting vectors is handled by pygmt.Figure.basemap.

Note

This tutorial assumes the use of a Python notebook, such as IPython or Jupyter Notebook. To see the figures while using a Python script instead, use fig.show(method="external") to display the figure in the default PDF viewer.

To save the figure, use fig.savefig("figname.pdf") where "figname.pdf" is the desired name and file extension for the saved figure.

import numpy as np
import pygmt

Plot Cartesian Vectors

Create a simple Cartesian vector using a starting point through x, y, and direction parameters. On the shown figure, the plot is projected on a 10cm X 10cm region, which is specified by the projection parameter. The direction is specified by a list of two 1d arrays structured as [[angle_in_degrees], [length]]. The angle is measured in degrees and moves counter-clockwise from the horizontal. The length of the vector uses centimeters by default but could be changed using pygmt.config (Check the next examples for unit changes).

Notice that the v in the style parameter stands for vector; it distinguishes it from regular lines and allows for different customization. 0c is used to specify the size of the arrow head which explains why there is no arrow on either side of the vector.

fig = pygmt.Figure()
fig.plot(
    region=[0, 10, 0, 10],
    projection="X10c/10c",
    frame="ag",
    x=2,
    y=8,
    style="v0c",
    direction=[[-45], [6]],
)
fig.show()

Out:

<IPython.core.display.Image object>