We sometimes want to change the bathymetry of a canal, a channel or a river from an external program (eg Matlab script, Scilab, R, etc) to do the optimization of profiles for example, or to calculate the sensitivity of certain variables to bathymetry parameters.

This can be done with a file named changebathy.txt, which must be located with the xml project file. The example \dat\ex32_lacguiers\LacGuiers_v1.xml uses this feature.

This file has the following structure:

We can have as many lines as we want. The format is free (’*’ in Fortran format), that is to say that the numbers can be separated by as many spaces as desired, or a priori also tabs.

On each line:

• the first number is the number of the reach
• the second number is the number of the section in that reach
• the third is the scaling factor in Y (lateral) that we want to apply
• the fourth is the scaling factor in Z (vertical) that we want to apply
• the fifth is the vertical offset of the bottom elevation, and therefore the entire section (in m)

When executing the calculation program (Fluvia or Sirene) the sections thus modified will be indicated in the control window.