I have done interpolation (IDW and Nearest Neighbour) in QGIS. But interestingly the output shows the wrong result. The area where I have a huge number of points results in a lower Z value (it is supposed to have a higher Z value). Is it because of the overlapping points?
Another doubt is that kriging algorithm does not show the predicted value (i.e. predicted value is not in the Z value range
80), though the output curve is meaningful. The prediction shows values in the range
-70 or so. What might be the reason?