Improvements for the Masking codes

current suggestions

1. Try masking nested domains simultaneously to avoid troubles like this.

2. Consider having both Grids and PE_mask preserve the coastline data file name into a global attribute. Then can grab this information for the Matlab version.

3. The netCDF variables ncseg & lcseg have identical names to the similar maximal dimensions. These are often confused (standard packages, i.e. getnc) with "coordinate variables" (e.g. COARDS convention). This leads to errors. Change the names.
   • maybe just append _used.

4. Currently the Matlab & FORTRAN versions produce a different ordering for the islands. This is unacceptably unsystematic. To correct this:
   1. Load the boundary indices in the FORTRAN version to mimic the Matlab ordering. This will give the initial lists with consistent ordering.
   2. Reorder the islands based on size. This is done for sequential resetting of streamfunctions around islands. Use the exact same sorting code for both versions. Measure size based on either
      • Length of island coastlines
      • Area (number of grid points) contained within island.

5. Create an option to initialize masks based on whether a point is inside GSHHS polygons.
   • Test against N-pole, not S-pole. Otherwise every point is inside Antarctica.

6. When GRIDS recognizes cyclic topography, PE_mask should produce masks with this feature.

7. In the Matlab version,
   • use the find function to get the starting points rather than looping over all possible starting boundary points.
     • Make sure to keep same ordering, PE_initial is paying attention to it.
   • display the coarse grid coastlines for nesting.

8. Update the FORTRAN version to:
   • have its own clean_mask function
   • use no_digit to control the format width for the printed flip point counter, currently limited to field width of 2.

9. Protect PE_mask against failing if no land is masked.
   • Matlab version is protected
   • check FORTRAN version

10. Possible useful annotations to Matlab version:
    • Write coastline number near coastlines. Improves ability of user to control transport streamfunction
    • writing mask to gname while writing mask
    • XX% Sea as title when done

11. Perhaps in clean_mask, should reflect near boundary to boundary. This would ensure 2 active points masked along boundary.

12. Rename this stuff HOPS_Mask?