Sorting Data points from a Curvature

Hello everyone. I have generated g-code developing a program in grasshopper for a curvature surface (which has both upward and downward slopes). Now I want to separate the data points/co-ordinates to two separate list according to upward or downward slopes. Can anyone help me with some ideas?
Thanks.

I’m guessing this is a Grasshopper question?
I’ve assigned your message to the Grasshopper category.