Feature #1019 USCRN

[JohnHalleyGotway]

This PR changes about 86 different source code files, however the vast majority of them are unrelated and modified only to drive down the overall number of SonarQube code smells. Here's a description of these modified files:

1. Documentation (1):

• docs/Users_Guide/reformat_point.rst has minor ascii2nc updates to the User's Guide.

2. Testing (1):

• internal/test_unit/xml/unit_ascii2nc.xml adds 1 new unit test for -format uscrn.

3. Application Code (7):

• src/tools/other/ascii2nc/Makefile.am and .in to compile newly added USCRN source code.
• src/tools/other/ascii2nc/ascii2nc.cc to support new -format uscrn option.
• src/tools/other/ascii2nc/file_handler.h and .cc parent class to track observation unit and description strings.
• src/tools/other/ascii2nc/uscrn_handler.h and .cc are NEW FILES which contain the meat of the work, defining how to read 7 different variations of this new data source!

4. Library Code (13):

• src/basic/vx_log/string_array.h and .cc add a new StringArray::all_empty() member function to check for an array of all empty strings which is used when deciding to write observation units and descriptions.
• src/basic/vx_util/data_line.h and .cc adds new DataLine::AllowEmptyColumns variable that used when parsing .csv input files. Also remove unneeded Offset vector which is a holdover from prior to the switch to using STL.
• src/basic/vx_util/observation.h and .cc and nc_points_obs_out.nc add members to store observation unit and description strings, needed to enhance ascii2nc to write them to the output
• src/basic/vx_nc_obs/nc_obs_util.h and .cc update logic for writing observation unit and description strings.
• src/libcode/vx_summary/summary_key.h and .cc and src/libcode/vx_summary/summary_obs.h and .cc update to store observation unit and description strings.

5. Everything else (86 - 22 = 64):

• Minor changes from using string::push_back() to string::emplace_back(), as recommended by SonarQube.
• Changes of some class members from protected to private, as recommended by SonarQube.

Expected Differences

• Do these changes introduce new tools, command line arguments, or configuration file options? [Yes]
  
  If yes, please describe:
  

• Adds support to ascii2nc for the new -format uscrn option. There are actually 7 different flavors of USCRN data, and all 7 are supported based on the naming conventions of the filename prefix and suffix.

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [Yes]
  
  If yes, please describe:
  

• This is small and subtle change. Previously, ascii2nc had the ability to write obs_units to the output NetCDF file, but this is only enabled for -format airnow data. When the obs_units variable is written to the output, then an obs_desc variable is also written for "descriptions". However, airnow doesn't populate those strings. This PR tweaks that logic, so that obs_units and obs_desc variables are only written if they are defined by non-empty strings. And that logic is handled independently for each. Note that -format airnow will now only write obs_units while -format uscrn will write obs_units and obs_desc. And this is the source of the unit test diffs described below.

Pull Request Testing

• Describe testing already performed for these changes:
  

• Ran manually several times on the command line and inspected the NetCDF output.

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

• @j-opatz please review the doc updates, new unit test output, and consider doing more throughly using seneca:/d1/projects/MET/MET_pull_requests/met-12.1.0/beta1/MET-feature_1019_USCRN. Also confirm the observation unit and description changes appearing the output.

• @georgemccabe please focus on the actual code changes and consider impacts to any METplus Use Cases that use AirNow input data.

• @anewman89 please validate the metadata added to uscrn_handler.cc (e.g. variable naming conventions, units, and descriptions) against the readme.txt files from the NCEI product subdirectories (https://www.ncei.noaa.gov/pub/data/uscrn/products/).

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes]
  I updated the ascii2nc chapter.

• Do these changes include sufficient testing updates? [Yes]
  I added a test to unit_ascii2nc.xml to demonstrate. It reads input for the Boulder location for all 7 supported data types and uses the -valid_beg/-valid_end options to extract observations only for 20240801 at 00Z.

• 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:
  

• Adds new ascii2nc/USCRN_Boulder_20240801.nc unit test output file.

• Modifies the following files by removing the obs_desc variable that only contains empty strings:

  • airnow/HourlyAQObs_20220312.nc
  • airnow/HourlyData_20220312.nc
  • airnow/daily_data_v2_20220312.nc

• Will this PR result in changes to existing METplus Use Cases? [Maybe]
  
  If yes, create a new Update Truth METplus issue to describe them.

• Differences will be flagged for any use cases that run ascii2nc with Airnow inputs.

• Do these changes introduce new SonarQube findings? [Yes or No]
  
  If yes, please describe:

• While some SonarQube code smells in "new code" are flagged, changes for this PR reduce the overall number of code smells from 18,060 down to 18,037. I did review the "new code" ones and fixed all the (relatively) easy ones.

• Please complete this pull request review by [Fri 1/17/25].
  

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[JohnHalleyGotway]

Needed some updates, but the SonarQube run is now working as it should. It did flag 41 "new" code smells and a total of 18,090 code smells overall, compared to 18,060 in the develop branch. So I'll do some work to reduce the overall number of code smells < 18,060.

[georgemccabe]

There are a lot of changes here, but they look good as far as I can tell. In addition to adding support for the uscrn obs, I see many improvements as suggested by SonarQube.

I will keep an eye out for differences in METplus use case output based on these changes, but as far as I know there are no existing use cases that use airnow data.

[j-opatz]

Documentation changes are good, along with the general idea of the PR. I reviewed the differences from GHA and confirmed they were as expected. Checked output from ascii2nc run using USCRN data and confirmed that both obs_unit and obs_desc are both present in the output netCDF file. I approve the PR.