Antialiased contourf plot shows unexpected artifacts #4086
Description
🐛 Bug Report
When plotting an iris cube with contourf in some circumstances an additional contour is shown. This appears to be related to the logic included by the antialiased option in iris.plot.contouf.
How To Reproduce
Steps to reproduce the behaviour:
- Contact @jamesp for data and reproduction script
Expected behaviour
Antialiased data should not show additional artifacts when plotting.
Screenshots
Environment
- OS & Version: Linux
- Iris Version: 3.0.1. Affects Iris >= 2.3