Hi Arthur,
I'll give you one answer and one suggestion :
- You should work with local coordinates using xy shifting.
15078
13551
- Your question suggest that you want to compare two simulation (with or without the island)... Did you know this interesting feature.
Element Masking
TELEMAC-2D offers the possibility of masking certain elements. This means, for example, that islands can be created in an existing mesh. The boundaries created in this way are processed as solid walls with a slip condition.
This option is activated with the logical keyword ELEMENTS MASKED BY USER (default value: NO). In this case, the user must indicate the number of elements masked by programming the MASKOB subroutine. This manages an array of real values MASKEL, the size of which is equal to the number of points and in which each value can be 0.D0 for a masked element and 1.D0 a normal one.