IMPORTANT: Added several Matlab scripts to manipulate grids

[arango]

I have several Matlab grid manipulation scripts that may be useful to some Users.

• cartesian_grid.m: Given a larger donor grid (D), this function extracts a rotated Cartesian grid centered at (Xc, Yc) and rotated by angle theta. The larger donor grid is used during plotting to display the location of the rotated grid.

• spherical_grid.m: Given a larger donor grid (D), this function extracts a rotated Spherical grid centered at (Tlon, Tlat) and rotated by angle alpha.

• grid_rotated.m: Given a larger Grid NetCDF file (Ginp), this function extracts and creates a rotated subdomain (Cartesian or Spherical) Grid NetCDF file (Gout) centered at (Xmid,Ymid) and rotated by angle theta.

• roms_metrics.m: Computes the several ROMS grid metrics from the (lon,lat) coordinates.

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I highly recommend using roms_metrics when building the ROMS GRID NetCDF file to have consistent grid variables. The function grid_metrics is deprecated. Use the robust roms_metrics instead. The grid_metrics function will be removed in the future.

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Notice that the rotated grids are experimental. They were designed to have rotated nested grids. Such capability is not available in the ROMS numerical kernel.