[Paraview] Measurement of area

[mariagrazia.madaschi at libero.it]

I need to determine the value of the area of a surface.

I generated a .vtp surface with a python code. With python a created an array 
which associates id 0 to points with particular features and 1 to all the other 
points. 
When I open the .vtp file with Paraview I display surface according to the 
array (0/1). 
I need to extract from the surface the value of the area formed by points with 
id 0.

Is there any way to do that?