So, I have three numpy arrays which store latitude, longitude, and some property value on a grid -- that is, I have LAT(y,x), LON(y,x), and, say temperature T(y,x), for some
Try the combination of inverse-distance weighting and scipy.spatial.KDTree described in SO inverse-distance-weighted-idw-interpolation-with-python. Kd-trees work nicely in 2d 3d ..., inverse-distance weighting is smooth and local, and the k= number of nearest neighbours can be varied to tradeoff speed / accuracy.