Describe the Enhancement

During the METplus MetOffice telecon on 6/10/21, @robdarvell described an issue he's run into when doing point verification on a global grid. He found 8 points located near the prime meridian that were counted by Point-Stat as being 'off the grid' and therefore excluded from the statistics. The MET library interpolation code translates those points from lat/lon space to grid x/y space and the grid-x value for these points are -1 < grid-x < 0.

This issue is to enhance MET to incorporate those points along the seam into the verification. Specifically, when processing global grids, handle points with x locations between -1 and 0 or between Nx-1 and Nx. Recommend addressing the following issues:

• Request test data from @robdarvell to replicate this behavior.
  • Please find sample data from Rob: kiowa:/d1/projects/MET/MET_pull_requests/met-10.1.0/met-10.1.0_beta2/feature_1823/input_data
• Check to see what handling of global grids currently exists (e.g. shifting global grids in MODE by some number of degrees). Is there any automated or configurable logic for identifying global grids? If not, consider adding both... so that they are automatically identified, but that identification can be overridden by a config file option.
• When stating "global" grids, we are talking about the x-dimension, indicating that the longitudes wrap. The latitudes need not extend all the way to the poles for this logic to be required.
• When processing these points on the seam, enhance the interpolation logic to interpolate between the first and last columns of grid values.

Time Estimate

Estimate the amount of work required here.
Issues should represent approximately 1 to 3 days of work.

Sub-Issues

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No sub-issues required.

Relevant Deadlines

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Funding Source

2799991

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Assignee

• Select engineer(s) or no engineer required: John HG
• Select scientist(s) or no scientist required: Rob D for now. Could have another METplus scientist advise on the changes and ask Rob to test.

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Define Related Issue(s)

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• METplus, MET, METdatadb, METviewer, METexpress, METcalcpy, METplotpy
  If configurable options are added, coordinate them with METplus wrappers.

Enhancement Checklist

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