Researchers analyzed acid precipitation data in Ontario using different methods to estimate spatial trends and uncertainties. They found that a new Modified Kriging method provided better interpolation and error estimation compared to Simple Kriging and Universal Kriging methods. The error estimates from Simple Kriging and Universal Kriging methods were higher than those from the Modified Kriging method, suggesting that the error estimations from Simple Kriging methods may be too high. Further research is needed to improve the Universal Kriging method by finding the correct covariance function.