Installing

For ParaView, the conda-forge build is the easiest, since the reader needs netCDF4 (or scipy) in ParaView’s Python:

conda create -n paraview -c conda-forge paraview netcdf4
conda activate paraview
pip install anuga-paraview

It is tested with ParaView 6.2; older 5.x releases may work but are untested.

For the web viewer alone, no ParaView or conda is needed:

pip install "anuga-paraview[web]"

The development version installs with pip install git+https://github.com/anuga-community/anuga_paraview.

Quick start

anuga-paraview starts ParaView with the reader loaded, and given a file, opens it with a ready-made view:

anuga-paraview            # open .sww files with File > Open
anuga-paraview run.sww

The bed is coloured by elevation and the water by depth, with water under 5 cm faded out so the terrain shows through, and the depth colour range fixed over the run. A time label sits in the corner; press Play on the animation toolbar. The setup is in scripts/view_sww.py: to apply it to a .sww opened with File > Open, select the file in the Pipeline Browser and run the script from View > Python Shell > Run Script, or add it once as a toolbar button with Macros > Import new macro.

The launcher uses the paraview on the PATH, or the one given by --paraview or $PARAVIEW, and runs it on X11 when the session is Wayland.

anuga-web-viewer run.sww serves the browser viewer; see Web viewer.

Loading

In the ParaView GUI, use Tools > Manage Plugins > Load New… and pick sww_reader.py, in the directory anuga-paraview --plugin-path prints. Tick Auto Load to have it every session. .sww files then open with File > Open like any other format.

From pvpython:

from paraview.simple import *
LoadPlugin('/path/to/anuga_paraview/plugin/sww_reader.py', ns=globals())
sww = OpenDataFile('run.sww')

To read files on a remote machine with pvserver, load the plugin on both the client and the server (the Manage Plugins dialog has a list for each), and install netCDF4 in the server’s Python.

Outputs

The reader has two outputs, matching anuga_viewer:

Bed

The terrain, with z = elevation.

Water

The water surface, with z = stage. Triangles whose three vertices are all shallower than 1 mm are left out, unless ShowDryWater is on.

Both carry the same arrays at each timestep:

• every per-point variable in the file (stage, elevation, xmomentum, friction, …) as point data;

• every per-triangle variable (stage_c, max_depth_c, …) as cell data;

• derived depth, and where momentum is present momentum, speed and a velocity vector, with speed zero where depth is below 1 mm. The same are derived per triangle (depth_c, speed_c, …) when the file has stage_c and elevation_c.

Properties

Point Arrays / Cell Arrays

Shown with the gear (advanced) button at the top of the Properties panel. The arrays the file offers, per point and per triangle, all ticked to begin with. Unticked arrays are not read, except where a ticked derived quantity needs them (speed reads both momentum components). Elevation and stage are always read, since the surfaces are built from them.

VerticalScale

Vertical exaggeration of both surfaces, like anuga_viewer -scale.

Georeferenced

Add the file’s xllcorner/yllcorner, giving projected (e.g. UTM) coordinates rather than the local ones stored in the file.

ShowDryWater

Keep dry triangles in the Water output.

ComputeMaxima

Add max_stage, max_depth, max_speed and max_momentum over all timesteps. This reads the whole file once.

Bed is coloured by elevation and Water by depth to begin with; speed is often more telling. ParaView fixes the colour range when you press Apply, which is usually the dry first timestep, so press Rescale to data range over all timesteps on the colour toolbar before playing the animation.

On Linux under Wayland, if ParaView hangs at startup, run it on X11:

QT_QPA_PLATFORM=xcb paraview

If it still hangs, add LIBGL_ALWAYS_SOFTWARE=1 to use software OpenGL.

Setting PV_PLUGIN_PATH to the plugin directory loads the reader without the Manage Plugins dialog:

PV_PLUGIN_PATH=$(anuga-paraview --plugin-path) paraview run.sww

The plugin is alone in that directory because ParaView loads every .py file on PV_PLUGIN_PATH as a plugin. It needs only numpy and netCDF4 (or scipy), so a ParaView with its own Python, such as the binaries from paraview.org, can load it by path without anuga_paraview being installed there.

Timeseries at a point

The plugin also adds an ANUGA Timeseries filter. It reads the values at one location straight from the file, so it is instant even for long runs, where ParaView’s Plot Selection Over Time re-reads every timestep in full.

1. Select Bed (or Water) in the Pipeline Browser.

2. Add the filter: Filters > ANUGA > ANUGA Timeseries, or Ctrl+Space and type “ANUGA”.

3. Click Apply. A line chart of depth and speed against time opens beside the 3D view, for the middle of the domain.

4. Move the location: click in the 3D view, hover over the spot and press P, or drag the marker, or type coordinates into Location. Then click Apply. For the chart to follow the marker without Apply, tick Auto Apply in Edit > Settings > General (under Properties Panel Options).

5. Tick other quantities under Quantities: stage, elevation, momentum and its components.

Values are interpolated from the corners of the triangle containing the location, as ANUGA’s own gauge tools do. Only x and y matter. File > Save Data writes the chart’s table as CSV.

Web viewer

anuga-web-viewer is a browser viewer built with trame. It reuses the reader’s file code with plain VTK, so it does not need ParaView:

pip install "anuga-paraview[web]"
anuga-web-viewer run.sww --port 8080

and open http://localhost:8080. The server reads the file and renders, and the browser only receives images, so a large file on a remote machine can be viewed through ssh -L 8080:localhost:8080 host. It shows the bed and water with a time slider and Play; the side panel sets the quantity the water is coloured by, the colour map and scale maximum, the depth below which water is hidden, and the vertical scale, and plots a timeseries at a picked point. It works with the vtk wheel from pip, which renders without a display (through EGL or OSMesa) on a headless server, and with the VTK in ParaView’s conda package. It serves one user at a time.

Testing

pip install -e ".[web,test]"
python -m pytest

checks the reader’s file code, the reader as a plain VTK algorithm, the web viewer and the launcher against the sample files in data/, comparing with values read directly from the files. In an environment with ParaView (conda install -c conda-forge paraview), the same command also checks the reader inside ParaView (tests/paraview/); elsewhere those tests are skipped.

Releasing

Set __version__ in src/anuga_paraview/__init__.py, merge, then publish a GitHub release tagged v plus that version (e.g. v0.1.0). The Release workflow builds the sdist and wheel, checks the tag matches the version, and uploads them to PyPI by trusted publishing.

License

Apache License 2.0, as for ANUGA.