Before you start a simulation you have to prepare the bathymetry in a data file or, in other words, digitise your model area. There are several ways to do this:
· Draw the computational grid on a piece of transparent paper, put it on top of the sea chart and write the depth for each grid node on the paper. Then enter the depth values in a file using the data file editor for 2D matrices provided with MIKE 21.
· If you have a digitising tablet compatible with the MIKE 21 digitising program you can use this to create a file with (x,y) coordinates and the corresponding depths. This data can then be gridded using the Bathymetry Editor facility of MIKE 21. An example with a step-by-step description of how to use the Bathymetry Editor is included with the installation. Please find this example in your installation folder under
Examples\MIKEZero\BatEdit.
· If you have your depth information in digital form you can create an ASCII file (.txt) and enter this file into the standard data file format using the Grid Editor.
In all cases please note that the depth given to a grid point represents not only the depth right at that point, but the area surrounding the grid point, see Figure 6.9.
Figure 6.9 Depth representation in the grid
