Bugfix #2979 main_v11.1 MTD Grid

[JohnHalleyGotway]

Expected Differences

MTD has custom code to read/write grid information from NetCDF input/output files. However, that custom code only supports Lambert Conformal, Lat/Lon, and Polar Stereographic grids. The fix in this PR replaces that custom code with calls to common library utility functions that support a wider variety of projections.

These changes for main_v11.1 are rather limited in scope.

• 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:
  
  However, these changes will result in negligible differences in the metadata of the NetCDF output from MTD.

Pull Request Testing

• Describe testing already performed for these changes:
  
  Manually ran MTD using NetCDF input files on a Mercator projection. The main_v11.1 version of mtd errors out due to the unsupported grid type, while this bugfix branch completes without error.

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

• Please review the code changes.

• Please find the code for this PR compiled on seneca:

/d1/projects/MET/MET_pull_requests/met-11.1.2/MET-bugfix_2979_main_v11.1_mtd_grid

• You can re-do the testing I did by running this script:

cd /d1/projects/MET/MET_pull_requests/met-11.1.2/MET-bugfix_2979_main_v11.1_mtd_grid/internal/test_unit/test_MET_2979
./run_mtd.sh

• Please also consider testing the original problem you encountered in the Python Embedding for plot_data_plane and MTD METplus#2691 discussion.

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes]
  None needed. I confirmed that the mode-td.rst User's Guide file makes no reference to specific projection types. So the assumption would be that all projections supported by other MET tools would also be supported by MTD.

• Do these changes include sufficient testing updates? [Yes]
  I thought about this and decided that none are needed. While we could add unit tests for running MTD with all possible projection types, that is not warranted. Testing all possible inputs for all of the MET tools is unnecessary, as long as all projection types are tested for at least one tool.

• Will this PR result in changes to the MET test suite? [Yes]
  
  If yes, describe the new output and/or changes to the existing output:
  
  I do expect trivial differences in the metadata of the NetCDF files written by MTD similar to those shown below:

COMPARING python/mtd_PYTHON_20050807_120000V_obj.nc
file1: /data/output/met_test_truth/python/mtd_PYTHON_20050807_120000V_obj.nc
file2: /data/output/met_test_output/python/mtd_PYTHON_20050807_120000V_obj.nc
ERROR: NetCDF headers differ:
3,4d2
< 	lon = 185 ;
< 	lat = 129 ;
5a4,5
> 	lat = 129 ;
> 	lon = 185 ;
44,52c44,53
< 		:scale_lat_1 = "25" ;
< 		:scale_lat_2 = "25" ;
< 		:lat_pin = "12.19" ;
< 		:lon_pin = "-135.459" ;
< 		:x_pin = "0" ;
< 		:y_pin = "0" ;
< 		:lon_orient = "-95" ;
< 		:d_km = "40.635 km" ;
< 		:r_km = "6371.2 km" ;
---
> 		:hemisphere = "N" ;
> 		:scale_lat_1 = "25.000000" ;
> 		:scale_lat_2 = "25.000000" ;
> 		:lat_pin = "12.190000" ;
> 		:lon_pin = "-135.459000" ;
> 		:x_pin = "0.000000" ;
> 		:y_pin = "0.000000" ;
> 		:lon_orient = "-95.000000" ;
> 		:d_km = "40.635000" ;
> 		:r_km = "6371.200000" ;
54c55
< 		:ny = "129" ;
---
> 		:ny = "129 grid_points" ;

• Will this PR result in changes to existing METplus Use Cases? [Yes]
  
  If yes, create a new Update Truth METplus issue to describe them.
  We probably can expect similar minor differences to what's shown above.

• Do these changes introduce new SonarQube findings? [Unknown]
  
  If yes, please describe:
  I do not intend to fix any SonarQube findings for this bugfix for the main_v11.1 branch.

• Please complete this pull request review by [Monday 9/30/24].
  

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[j-opatz]

MTD now calls the main library function for reading/writing netCDF files, allowing full projection support.
Tested this PR and its Seneca-compiled location against the Discussions issue that brought this to our attention and confirmed it now works as expected.