best 3D visualization tool for ROMS

[sonaljit.m]

Hi. I need to use a 3D visualization software for ROMS outputs. Most visualization tools use a Cartesian coordinate system. But since the ROMS outputs are in terrain following sigma coordinates, I have to interpolate the sigma grid to a Cartesian grid, which is time consuming. Is there a good visualization tool available for ROMS, which can directly visualize the output fields in 3D?

Thanks.

[MIDHILAVARNAV]

ROMS tools (Matlab based) have a romsgui function, an interactive visual toolbox. ( The link http://forge.ipsl.jussieu.fr/roms_locea ... order=name). Pl Check folder visualisation tools

[wilkin]

I have written code (roms_isosurface.m) to use Matlab's isosurface function to create 3D visualizations. This is part of my roms_wilkin toolbox at https://github.com/johnwilkin/roms_wilkin

Some examples are shown below generated by roms_isosurface_demo.m in the GitHub repo.The demo calls an OPeNDAP URL for ROMS output, so anyone can reproduce these plots by running the demo.

As you noted, Matlab isosurface works in uniform spacing Cartesian space, but ROMS native i,j,k is such a space. The magic in roms_isosurface.m is to create griddedInterpolant classes that convert i,j,k space to ROMS lon,lat,z space. The isosurface is rendered in i,j.k space but then the isosurface vertices are converted to lon,lat,z before the surf function is called to display.

Creating the griddedInterpolant classes is very straightforward:

Code: Select all

% Isosurface works in plaid i,j,k space, so the surface will be rendered 
% in i,j,k coordinates that will then be mapped to lon,lat,z for display.
% This is by far preferable to regridding the data to a uniform lon/lat
% grid.

% set up the i,j,k, to lon,lat,z transformation
[I3,J3,K3] = ndgrid(1:size(data,1),1:size(data,2),1:size(data,3));
[I2,J2] = ndgrid(1:size(data,1),1:size(data,2));

Fx = griddedInterpolant(I2,J2,permute(g.lon_rho,[2 1]));
Fy = griddedInterpolant(I2,J2,permute(g.lat_rho,[2 1]));
Fz = griddedInterpolant(I3,J3,K3,permute(g.z_r,[3 2 1]));

% get the isosurface in i,j,k space
S = isosurface(I3,J3,K3,data,value);
Snew = S;

% convert fractional i,j to lon/lat and fractional k to z by interpolation
Snew.vertices(:,1) = Fx(S.vertices(:,1),S.vertices(:,2));
Snew.vertices(:,2) = Fy(S.vertices(:,1),S.vertices(:,2));
Snew.vertices(:,3) = Fz(S.vertices(:,1),S.vertices(:,2),S.vertices(:,3));