Annotating throats at a certain location

[mourendong]

Hi, everyone,
I try to mark the throat at a certain location, but I did not find a way to do it.
For example, the length of the throat is 2.5e-10, and I want to mark the location of 1.0e-10, just like the picture I added manually (the black dot).

Can you give me some advice on how to do it?

[jgostick]

You have a few options, but they all involve finding the [x,y,z] points you want to plot, so let's start there. For each throat in the network you can find it's centroid (as the average of the neighbor) using crds = np.mean(pn.coords[pn.conns], axis=1)

To plot them you can either (a) add them to your network (mangling your current network) (b) create a new network and plot them together or (c) update a custom version of our plot function to add them. I think option b is the best bet:

pn = op.network.Cubic([5, 5, 1])
crds = np.mean(pn.coords[pn.conns], axis=1)
pn2 = op.network.GenericNetwork(Np=crds.shape[0], Nt=0)
pn2['pore.coords'] = crds
ax = op.topotools.plot_coordinates(pn, c='g')
ax = op.topotools.plot_connections(pn, ax=ax)
ax = op.topotools.plot_coordinates(pn2, ax=ax, c='r')

[mourendong]

Thanks for your kind reply!
The code as you write expresses the results, but I'm still a little confused.
As the example, the length of the throat is 2.5e-10, how to mark any location of the throat, if the point in the length of 1.0e-10, 0.8e-10, or 2.3e-10.
Maybe your reply involve it, I'm still a little confused about it.
Many thanks for your help!

[jgostick]

You'll need to alter the line: crds = np.mean(pn.coords[pn.conns], axis=1) to generate the coordinates you which to plot. I thought you wanted the 'mid-point' of the throat. If you want some other point then you need to compute it as required. The end result should be an Nt by 3 array of [x,y,z] coordinates, which you can then use as 'pore.coords' in a new fake network for the purposes of plotting.

[mourendong]

Many thanks for your kind explanation, I got it!