Grid search technique to overlap data matrices with different dimensions

Hello everybody I was trying to use data after merging it in grid

data- 1
20.3250  50.1234  1.0000
21.3690  51.2365  21.0000
23.6987  52.6398  36.0000
24.6980  53.6987  65.0000
25.1456  56.2583  62.0000
26.6987  54.2146  35.0000
23.6589  52.3655  24.0000
25.6358  58.9654  15.0000
22.5698  57.3698  15.0000

data-2 
20.3610  50.1594  1.5000
21.4050  51.2725  21.5000
23.7347  52.6758  36.5000
24.7340  53.7347  65.5000
25.1816  56.2943  62.5000
26.7347  54.2506  35.5000
23.6949  52.4015  24.5000

Now I want to use nearest nehbour so that I want grid data with lets say 0.01 degree and anything in or at the boundaries of grid will fall inside the grid. ignoring thrd column which can be the smartest approach to do this?

Thanks, Amb