warp u and v grids, instead of speed and direction grids, to avoid angle interpolation errors #645
Description
wxModels that read in speed and direction grids, instead of u and v grids, need to be warped as u and v grids NOT speed and direction grids, to avoid angle interpolation errors. Gdal warp interpolations in our code base do not handle periodic values.
I looked over the various wxModel initializations for the angleFromNorth work, and saw that ncepNdfdInitialization.cpp (UCAR-NDFD-CONUS-2.5-KM) is warping speed and direction grids, not u and v grids. Looks like the new "nbm_conus" model in nomads_wx_init.cpp (NOMADS-NBM-CONUS-2.5-KM) is also warping speed and direction grids, not u and v grids as well.
The whole code base should be checked/watched out for any other instances of warping speed and direction instead of u and v, but I'm pretty sure those were the only instances that I saw while looking over so much speed, dir, u, v code during the angleFromNorth project.
Need to keep this rule in mind for any future code additions.