The format of the deviation can be specified as
· Constant (in domain)
· Varying in domain
For the case with varying in domain you have to prepare a data file containing the deviation (in component unit) before you set up the hydrodynamic simulation. The file must be a 2D unstructured data file (dfsu) or a 2D grid data file (dfs2). If a dfsu-file is used the mesh in the data file must match exactly the mesh in the simulation. If a dfs2-file is used the area in the data file must cover the model area. Bilinear interpolation is used to map the data. In case the input data file contains a single time step, this field is used. In case the file contains several time steps, e.g. from the results of a previous simulation, the actual starting time of the simulation is used to interpolate the field in time. Therefore the starting time must be between the start and end time of the file.