1. A regionalization method comprising: inputting a data set into a computer; utilizing the computer to perform contiguity-constrained hierarchical clustering on the data set to generate two regions while minimizing information loss associated with the regions, the information loss being defined in terms of the sum of squared distances; and performing a fine-tuning optimization procedure on the two regions with the computer to iteratively modify the boundaries between the two regions while minimizing information loss by moving at least one data point from one region to the other while maintaining the contiguity of each region to enhance partition quality.