Figure.plot fails to plot lines correctly

Description of the problem

Figure.plot() doesn’t plot simple lines correctly.

Full code that generated the error

import pygmt

fig = pygmt.Figure()
fig.basemap(J="X8c/8c", R="-10/10/0/10", B=True)
fig.plot(x=[0.0, 0.0], y=[0, 10], W="1p,gray,-")
fig.plot(x=[5.0, 5.0], y=[2, 8], W="1p,gray,-")
fig.plot(x=[3.0, 8.0], y=[0, 10], W="1p,gray,-")
fig.show(method="external")

Output plot

Only the first line is correct. The other two lines are wrong.

System information

• Operating system: macOS
• Python installation (Anaconda, system, ETS): Anaconda
• Version of GMT: 6.0.0_15a9160
• Version of Python: 3.7.0
• Version of this package: latest
• If using conda, paste the output of conda list below

[seisman]

The issue is caused by a GMT bug. See https://github.com/GenericMappingTools/gmt/issues/3330 for the detailed bug report. The bug was already fixed in PR https://github.com/GenericMappingTools/gmt/pull/3331 and the script above should work with the upcoming GMT 6.1.0 release.

I added an upstream label to this issue and keep the issue opening, as I don’t think we can/should do any hacking on the PyGMT side.

Since plot() is one of the most commonly used functions, I propose that, when GMT 6.1.0 is released, we should:

• release PyGMT v0.1.1 or v0.2.0, and bump the minimum required GMT version to 6.1.0
• add the example script to the test

[seisman]

Using data instead of x and y also works.

import pygmt
import numpy as np

fig = pygmt.Figure()
fig.basemap(J="X8c/8c", R="-10/10/0/10", B=True)
fig.plot(data=np.column_stack([[0.0, 0.0], [0, 10]]), W="1p,gray,-")
fig.plot(data=np.column_stack([[5.0, 5.0], [2, 8]]), W="1p,gray,-")
fig.plot(data=np.column_stack([[3.0, 8.0], [0, 10]]), W="1p,gray,-")
fig.savefig("lines.png")