pointwise.f90 was written as a way of interpolating scattered data on to the elmer mesh. It may be superceded by Grid2DInterpolator (though it uses a different algorithm). Not properly documented yet, but see comments in the pointwise.f90 file for usage.
Note, if pointwise is used several times within one sif-file, the corresponding .so file needs to be duplicated under a different name (see also Flowdepth Solver), i.e. pointwise1.so and pointwise2.so.