Support transect difference plotting and aggregation

[James Warner (jwarner8)]

Addresses #2025

Contribution checklist

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• Documentation has been updated to reflect change.
• New code has tests, and affected old tests have been updated.
• All tests and CI checks pass.
• Ensured the pull request title is descriptive.
• Ensure rose-suite.conf.example has been updated if new diagnostic added.
• Conda lock files have been updated if dependencies have changed.
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[github-actions]

[James Warner (jwarner8)]

Transect differences working (with aggregation), but adding some more code to enforce the ordering of pressure levels in case they are defined different in UM/ML models, like this...

[James Warner (jwarner8)]

Now much better, likely linked to #1535 too (threaded through for all transect recipes).

[James Warner (jwarner8)]

All options now working with separate sections in webpage, have also changed alpha of inset so that it doesn't cover all of the plot details.

This is still well visible when the anomalies are small, and white is used

[James Warner (jwarner8)]

TODO

• Update code comments, tidy
• Figure out why aggregate difference by hour of day isn't working, and whether we need to ensure _extract_common_time_points first? As models have different output frequencies. Solution: wasn't using forecast_period.
• Ensure GUI is descriptive
• Add additional recipes for other aggregation difference types (lead-time, valid-time, hour of day).
• Combine increasing levels with existing misc check/functionality (decided against)
• Py testing!!! ;-)

Tests required...

• _slice_cube_on_common_levels (check that it returns correct subset)
• extract_common_pressure_levels (ensure that only a CubeList containing two cubes is passed into function.
• extract_common_pressure_levels (if cube without pressure is tried, it should return ValueError.
• extract_common_pressure_levels (generic test to check that it returns two cubes with common pressure levels, remove one slice from test cube and then see if we can equate pressure points after going through function).
• extract_common_pressure_levels (check that if there are no matching levels it returns a ValueError, can manually change a cube to test this).

[David Flack (daflack)]

Looking good, one typo and requests for some more testing.

1. Can we get a test(s) that cover line 309-312 in misc.pycurrently all tests skip these lines.
2. Can we increase coverage in transect.py - needs tests for L136 (if statement false), L165 - to test the exception works, and L174 is currently always true - if expected can be an else, if not and something happens (even if yet to be implemented) when statement is false can this be tested as well please.

Haven't run it yet, but otherwise is looking great.

[James Warner (jwarner8)]

Looking good, one typo and requests for some more testing.

1. Can we get a test(s) that cover line 309-312 in misc.pycurrently all tests skip these lines.
2. Can we increase coverage in transect.py - needs tests for L136 (if statement false), L165 - to test the exception works, and L174 is currently always true - if expected can be an else, if not and something happens (even if yet to be implemented) when statement is false can this be tested as well please.

Haven't run it yet, but otherwise is looking great.

• Updated typo
• Add test for misc if plevs are wrong way round in one cube
• Fix transect L136 to else (was bug before), and tested in plotting.
• L165 test case for longitude, and ensure this is used as output transect coordinate. Links to 174 always true

[James Warner (jwarner8)]

Now correctly switches to longitude on x axis when this varies more than latitude

[James Warner (jwarner8)]

Test coverage now 100% for transect.py, ready for final review.

[David Flack (daflack)]

Happy with these changes, thanks for adding the extra tests.