the elevation of each vertex in the stage

[842590879]

Hello, how can I obtain the elevation of each vertex in the stage?

[stoiver]

Hi @842590879 The answer to your question is actually a little complicated than it might seem depending on how you want to use the the result.

Within the python script you can obtain the values via

stage_vv = domain.quantities['stage'].vertex_values

By the way centroid values similarly can be accessed via

stage_cv = domain.quantities['stage'].centroid_values

If you are running in parallel, these will only access the data on the specific processor.

I would recommend using centroid values as these are essentially uptodate where as vertex values are only guaranteed at the end of a yield step.

You can also access the stage values stored in the sww file, but of course the values will only be available at the yield timesteps. Checkout the SWW_dplotter interface.

[842590879]

Hi@stoiver, I am trying to achieve a flood effect in cesium, similar to the effect rendered by 3d anuga-viewer. But I found that the vertex_values method using domain.quantities['stage'].vertex_values gave the same vertex elevation. I also tried to change the value of the location parameter in the domain.set_quantity function, but the result was the same. So how do I get the different elevation values for each vertex of each triangle? Thank you very much!

[stoiver]

@842590879 are you pulling the data from an sww file (like the viewer) or in real time during a simulation?

[842590879]

@stoiver Real-time data extraction in the Merewether Flood Case Study Example
vertex = []
for t in domain.evolve(yieldstep=20, duration=300):
dplotter.save_depth_frame(vmin=0.0, vmax=1.0)
domain.print_timestepping_statistics()
vertex.append(domain.quantities['stage'].vertex_values.tolist())
dplotter.make_depth_animation()

[stoiver]

@842590879 How are you using the object vector?
The array domain.quantities['stage'].vertex_values is an array with 3 values for each element (triangle). There will be different vertex values for a given vertex location. The vertex values generate a piecewise linear function which is generally discontinuous across edges of the triangles.

Be aware that the size of vector which will grow as the evolution progresses.

[842590879]

@stoiver Thank you very much for your explanation.