Run the case

A case that passed the check runs in HydroPol2D MATLAB or in HydroPol2D Studio, depending on what you chose under Prepare for. The run panels appear below the result of the check, both after Prepare complete case and on Check a case.

Prepared for	Run it in	From
HydroPol2D MATLAB	HydroPol2D MATLAB (open source)	the Run HydroPol2D MATLAB panel, or MATLAB itself
HydroPol2D Python	HydroPol2D Studio	Open existing model in Studio, with hydropol_python/case.yaml
Python and MATLAB	either	both

In HydroPol2D MATLAB, from the app

You need MATLAB on your computer. The panel Run HydroPol2D MATLAB has:

• HydroPol2D MATLAB folder: a folder with the HydroPol2D MATLAB code. A folder that already holds it is used as it is, without updating it. If the folder does not exist, the app downloads HydroPol2D from its GitHub repository (main branch) into it. That download needs Git.
• MATLAB executable: found by itself when MATLAB is installed in the usual place. Otherwise give its path, for example /Applications/MATLAB_R2025b.app/bin/matlab on a Mac or C:\Program Files\MATLAB\R2025b\bin\matlab.exe on Windows.

Run HydroPol2D MATLAB starts MATLAB in the background. The button is active only after the check passed. Refresh status updates the page while the model runs:

• the state ("MATLAB is running in the background", "MATLAB simulation completed successfully", or the exit code when it stopped);
• a progress bar with the stage and the share of simulated time;
• Simulated time, Time step, Elapsed and Estimated remaining;
• the mean and maximum rainfall, the maximum depth, the outlet discharge, the total storage, the mass-balance error and the mean groundwater depth;
• the MATLAB run log, open by itself when the run fails.

When the run is complete, Results shows the maximum surface-water depth as a number, a map and an animation, and names the maximum-depth GeoTIFF for a GIS. The status and the logs are in model_runs/ inside the case, and the results in Outputs/.

In HydroPol2D MATLAB, by hand

The case's run_case.m sets the case paths, dates, resolution, rainfall, boundary conditions, outputs and execution options, then starts HydroPol2D. In MATLAB:

addpath('/path/to/CASE_DIR/hydropol_matlab')
run_case('/path/to/HydroPol2D')

The first path is the case folder, the second your HydroPol2D MATLAB folder. run_case.m does not change the configuration files of HydroPol2D: it passes the case to the model in memory, so the same HydroPol2D folder can run many cases. A case on the native mesh (a quadtree grid, an Urban Area Only case, or hydraulic tables) runs on the native mesh solver of HydroPol2D and writes a native mesh result archive. See the MATLAB workflow for the model itself.

In HydroPol2D Studio

1. Open HydroPol2D Studio.
2. On Home, choose Open existing model.
3. Choose hydropol_python/case.yaml in the case folder.

The case opens in Setup, ready to check and run. From there Studio's tools work on it, for example urban drainage, ponds, green infrastructure, crossings, results and calibration. See the Studio guide.

The app's Run HydroPol2D Python panel asks for a folder that holds HydroPol2D Python. The app does not download HydroPol2D Python, which comes with Studio. Without such a folder the panel says so and points to Studio.

Where the results go

Run	Results
MATLAB, regular grid	Outputs/, with the result previews in Outputs/PostProcessing/
MATLAB, native mesh	Outputs/Modeling_Results/Native/unstructured_results.nc and the previews
Python	Outputs/python/Modeling_Results/: figures, static GeoTIFFs and animations

The saved maps and their interval follow Saved outputs (Case settings).