When Creating an Iso surface (2 D) using grid as a surface constant I only get 0D facets created when I select a surface from the surface box. When I do not select a surface the default forms both 0D and 1D facets. Thus I can not section out flow average values across selected surfaces using surface intergrals. The areas will not be computed unless there are 1D Facets. Does anyone have any idea how to use the iso surface across a selected surface and get 1D facets?

When you create an iso-surface in 2D based on a "2D-surface" (i.e. an edge) you should get a single point, because you are cutting an edge by a constant of the coordinate system.

For creating a line as you are intending to do you should NOT select an additional surface from the surface box, but jsut a value for the grid constant.