Feature 2215 ioda2nc message type

[hsoh-u]

• Added "station_ob" variable to message_type variable name list (metadata_map at config file)
• Added "station_id" variable to station_id variable name list (metadata_map at config file)
  • Not include XXX@RecMetaData into the metadata variable list
  • "station_id@RecMetaData" variable with dimension (nrecs, nstring) is different from "station_id@MetaData" variable with different dimension (nlocs, nstring).
  • No additional variable is available and not know how to map station_id from "station_id@RecMetaData"
• If the message type metadata variable does not exist, set the message_type to "NA" instead of empty string "". This gives an option which prevents from filtering out by message type with the following MET tools
  • The empty message_type can not be mapped to any other existing message types
  • By having message_type "NA", they can be mapped to other message type

Expected Differences

• 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:
  

Run unit test.

• the unit test "ioda2nc_var_all" will have the log message

DEBUG 1: process_ioda_file() -> The metadata variable for message type does not exist!
DEBUG 1: process_ioda_file() -> The metadata variable for station ID does not exist!

ioda2nc adds the message_type and station_id with seneca:/d1/personal/kalb/ioda/raob_all_v1_20201215T1200Z.nc4 with new IODA2NCCondig_default.

/d1/personal/hsoh/data/IODA_files/raob_all_v1_20201215T1200Z.nc4 out_raob_all_v1_20201215T1200Z_msg_type2.nc -config IODA2NCConfig_msg_type -obs_var air_temperature -v 4

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

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

• Do these changes include sufficient testing updates? [No]

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

The unit test "ioda2nc_var_all" does not have the message_type and station_id variables. The hdr_typ_table was "". It will be changed "NA" at ioda2nc/odb_sonde_16019_all.nc.

• Please complete this pull request review by [Fill in date].
  

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 Linked issues 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.

[JohnHalleyGotway]

I approve of this PR.

Note that I did just update reformat_point.rst to make it consistent with the newly update ioda2nc config file. I reviewed the code changes and they look fine. I also inspected the diffs in the regression test output and see that this empty string:

ncdump -v hdr_typ_table odb_sonde_16019_all_TRUTH.nc
 hdr_typ_table =
  "" ;

Has now been corrected to be a non-empty "NA" string:

ncdump -v hdr_typ_table odb_sonde_16019_all_OUTPUT.nc
 hdr_typ_table =
  "NA" ;

@hsoh-u please proceed with the merge when you're ready and close issue #2215.