how to know which data that scattered above contour plot are belong to negative contour?

I have 2 different data, one 3d for the contour and other 2d data, I plot 3d data with contour function and got the contour map, then I plot 2d data above that contour so it is like scattered dot above contour map. I want to know which data from my 2d data is belong to the negative contour and which belong to positive contour? I try with contour fill but my data is too many, I can not observe one by one. I want to do this programmatically

Thank you. Adhi