Updated seagrid2roms matlab script

[arango]

The SeaGrid Matlab GUI was written by Chuck Denham around 1999 and its becoming out of date as Matlab continue to evolve and retire obsolete functions. This GUI has always work for me with Matlab 2006b. The update here is to work with newer versions of Matlab. I tried Matlab R2010a which is installed on my iMac. In order to get SeaGrid working I have to make few changes.

It also has been reported in the past that the script seagrid2roms.m which is used to write the ROMS NetCDF from the seagrid.mat file generated by SeaGrid. The NetCDF interface inside Matlab has also evolved substantially. There are several messages about this in the ROMS forum. This issue has been in my to do list for very long time. So I finally took some time to look at these reported problems. I rewrote seagrid2roms.m to work with the mexnc interface. Notice the this script now uses:

• matlab/grid/c_grid.m to create ROMS Grid NetCDF
• matlab/landmask/uvp_masks.m to compute the masks at U-, V-, and PSI-points
• matlab/utility/nc_write.m to write data into Grid NetCDF file

I did noticed that SeaGrid gives a nonzero rotation angle even if the grid is not rotated. The values are of the order 1E-12. I don't know if this is a round off error or there is something wrong in that computation. SeaGrid is complicated and has a logic that it is very difficult to follow. I am adding this in my to do list to track this computation inside the GUI in the future.

I also added a new script:

• matlab/utility/nc_drename.m: Generic script to rename a NetCDF dimension.