Feature #2565 nccf_laea

[JohnHalleyGotway]

Expected Differences

This Pull Request consists of 3 main changes:

1. Restore support for parsing LAEA grids from CF-compliant NetCDF files.
2. Fix support for parsing LAEA grids from GRIB2 files.
3. Add the configure and make logs to the output artifacts created by the MET compilation step of GHA.

• Do these changes introduce new tools, command line arguments, or configuration file options? [No]
  
  If yes, please describe:
  

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [No]
  
  If yes, please describe:
  

Pull Request Testing

• Describe testing already performed for these changes:
  
  Manually tested with CF-compliant NetCDF and GRIB2 inputs and confirmed that they work as expected.

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  

  • Please review the code changes.
  • Please review the small change to the documentation.
  • Note the differences in the unit tests described below.
  • Download the artifacts from this GHA run and confirm that the logs now include the following:

MET-feature_2565_nccf_laea-PR_make_test.log
MET-feature_2565_nccf_laea-PR_make_install.log
MET-feature_2565_nccf_laea-PR_configure.log

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes]

• Do these changes include sufficient testing updates? [Yes]
  Added a new LAEA test for cf-compliant NetCDF data.

• Will this PR result in changes to the test suite? [Yes]
  
  If yes, describe the new output and/or changes to the existing output:
  

All the unit tests run without error but 2 differences are flagged.

1. Add new output from plot_data_plane for CF-compliant NetCDF LAEA data.

ERROR: folder /data/output/met_test_truth missing 1 files
    plot_data_plane/air_temperature_laea_nccf.ps 

Compare this to the plot of this data produced by panoply:

2. The plot_data_plane output for the existing GRIB2 LAEA data is modified:

COMPARING plot_data_plane/ukv_agl_temperature_laea_grib2.ps
file1: /data/output/met_test_truth/plot_data_plane/ukv_agl_temperature_laea_grib2.ps
file2: /data/output/met_test_output/plot_data_plane/ukv_agl_temperature_laea_grib2.ps

Old on the left and new on the right:

The difference is an ever so subtle change in the orientation of the map outlines. They used to be tilted more left and are now more upright. This is caused by a fix to the central longitude value that's parse for this grid:
Old wrong value:

DEBUG 4:           central_lon: 10.0164

New correct value:

DEBUG 4:           central_lon: 2.5

That value of 2.5 is confirmed correct in the output from wgrib2 (ignore the difference in sign... that's degrees east vs west):

	Lambert Azimuthal Equal Area grid: (1042 x 970) input WE:SN output WE:SN res 48
	Lat1 44.517153 Lon1 2164.600777 Cen Lon -2.500000 Std Par 54.900000
	Dx 2000.000000 m Dy 2000.000000 m mode 48

Note that I submitted this as an issue in the grib2c GitHub repo:
NOAA-EMC/NCEPLIBS-g2c#427

• Please complete this pull request review by [Monday 7/24/23].
  

Pull Request Checklist

See the METplus Workflow for details.

• Review the source issue metadata (required labels, projects, and milestone).
• Complete the PR definition above.
• Ensure the PR title matches the feature or bugfix branch name.
• Define the PR metadata, as permissions allow.
  Select: Reviewer(s)
  Select: Organization level software support Project or Repository level development cycle Project
  Select: Milestone as the version that will include these changes
• After submitting the PR, select Development issue with the original issue number.
• After the PR is approved, merge your changes. If permissions do not allow this, request that the reviewer do the merge.
• Close the linked issue and delete your feature or bugfix branch from GitHub.

[jprestop]

I'm not sure if it's worth it, particularly with the time crunch, but I was wondering if we should consider creating a variable for the 1000000.0 value, which is reused?

[JohnHalleyGotway]

Good point Julie. Thanks for mentioning that. I'd like to not make a change at this time because it would apply to about 40 lines of code in this file. I'd rather limit the changes to what's explicitly necessary for this issue during the official release testing time period to limit the lines of code I touch. But this would be good to consider as part of the changes to the vx_grid library's use of the proj library in the future.

[jprestop]

I reviewed the code changes, reviewed the small change to the documentation, noted the differences in the unit tests as described in the PR description, and downloaded the artifacts from this GHA run and confirmed that the logs now include the log output from all compilation steps. Thanks for getting that working, @JohnHalleyGotway. Having those logs will be very helpful. I approve this PR.