open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello

Sorry for this late reply.
Actually you are not computing the real area of your polygon. If you see the small program updoaded by Jean Michel, you will see that the area is computed only using the coordinates of the vertices of the polygon. However, you are computing the area using a sum of T1 which are the areas of P1 bases of all the nodes that are inside your polygon. These are two different things.

I hope that this helps

with my best regards

Riadh

OK Riadh,

I understand, so either I calculate the area of the polygon using the concise program uploaded by JMH or I increase the resolution of my mesh to reduce the error when using the INPOLY function and area calculated from triangles.

Thanks for the reply.

M