Ocean boundary nodes

[yunfangsun]

Hi @SorooshMani-NOAA ,

When I am using Ocsmesh to plot the ocean boundary nodes by using

mesh_obj_2 = ocsmesh.Mesh.open('wave_obc/hgrid.gr3', crs=4326)
base_mesh = mesh_obj_2

base_mesh.boundaries.ocean().plot(ax=ax_tidal_5, color='b', label='Ocean')
base_mesh.boundaries.land().plot(ax=ax_tidal_5, color='r', label='Land')

It gives

However, when I use

boundaries_df = base_mesh.boundaries.ocean()

for index, row in boundaries_df.iterrows():

    index_ids = row['index_id']
    
    for index_id in index_ids:
        print(f'Index ID: {index_id}')
        
        with open('wave_obc/index_ids_2.txt', 'a') as f:
            f.write(f'{index_id}\n')

It gives me 334 points, and when I do scatter plot, it shows

Where some interior nodes are shown, could you please let me know how to take out the ocean boundary node id correctly?

Thank you!

[SorooshMani-NOAA]

I think it's just an issue of mixing IDs vs indices, you need to subtract 1 from the index_id to be able to get the correct nodes:

ax = m.boundaries.ocean().plot()
ax = m.boundaries.land().plot(ax=ax)
ax.scatter(*(m.msh_t.vert2['coord'][[i - 1 for i in gdf.index_id.loc[0]]].T))
plt.show()

Note that you have some places like this on your boundary which is not completely straight:

[yunfangsun]

Hi @SorooshMani-NOAA,

Is there an easy way to make the boundary straight? Thank you!

[SorooshMani-NOAA]

No, that's on my wishlist for OCSmesh!