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1. Determine the origin (xori, yori), spatial resolution (dx, dy), orientation (rot) and maximum bed level required (zmax) from the specified values in Dashboard.
2. Create a full grid between these points (+ some buffer of 5%) based on the bathymetry active in Dashboard (default this is GEBCO ’08).  This grid will already be defined in the active coordinate system the user specified (default this is WGS 84) .
3. Creation a rectangular grid within the boundaries specified in Dashboard. The grid cells which are above a certain bed level (zmax) are deleted. A linear interpolation is carried between the full grid and the rectangular grid within the boundaries

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The (rectangular) grid defined with also needs a bathymetry. When the user clicks on ‘Create bathymetry’, the following routines will then be called:

1. Determine which datasets are used and within which limit (zmin and zmax). This feature is especially handy when a different data set is used for the sea part and the land part. An offset can be used in order to shift the bathymetry. Diffusion is used in order to define depth values for missing data (NaNs).
   1. If in quick mode ‘make bathymetry’ is used the active bathymetry in Dashboard (default GEBCO ’08) is applied
   2. Other bathymetry sets can be important via ‘Bathmetry’ in the Working Space. 
2. The function will now loop over the different dataset datasets described.
   1. The bathymetry is first loaded.
      1. This can be downloaded from the OpenDAP server
      2. Or from your local directory file if the data needed is used in a previous set-up.
   2. Bathymetry is applied in the order defined.
   3. Interpolation from the original grid to the model grid is carried out with a linear interpolation. Only values (that are not NaNs) are taken into account.
3. If an internal diffusion is applied the remaining non existing bed levels are filled in based on the mean bed level and after that a smoothing function is applied. This option can be selected in the Working Space under 'Bathymetry'
4. If a model offset is applied the whole bathymetry is shifted. An offset of 1 meter means the bed level will be 1 meter lower than the original.
5. The bathymetry created is directly visible in Delft Dashboard.
   
   

Figure: The bathymetry created for New Zealand. The colors in Delft Dashboard are updated based on the value defined to the specific grid cell

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