I am attempting to export x location, y location, and data point (x,y) from a surface (.xdmf file format) at a particular time step for further analysis or plotting in python, matlab, r, etc.

Iâ€™ve attempted to select points within a polygon, but the magnitudes, which should correspond to surface variable W, are way to large. So I am unclear as to what the â€śPointsâ€ť and â€śPoints Magnitudeâ€ť actually correspond to.

Points are the position of the points.
PointsMagnitude is an automatic (albeit non-nonsensical in this context) magnitude computation value for any vector in the spreadsheet.

If you are looking to see the W values at the probe points, you have to switch to show the â€śProbe Filterâ€ť â€śCell Dataâ€ť in the spreadsheet view.