Supervised Spatial Regionalization using the Karhunen-Loève Expansion and Minimum Spanning Trees
Volume 20, Issue 4 (2022): Special Issue: Large-Scale Spatial Data Science, pp. 566–584
Pub. online: 9 November 2022
Type: Statistical Data Science
Open Access
Received
1 September 2022
1 September 2022
Accepted
30 October 2022
30 October 2022
Published
9 November 2022
9 November 2022
Abstract
The article presents a methodology for supervised regionalization of data on a spatial domain. Defining a spatial process at multiple scales leads to the famous ecological fallacy problem. Here, we use the ecological fallacy as the basis for a minimization criterion to obtain the intended regions. The Karhunen-Loève Expansion of the spatial process maintains the relationship between the realizations from multiple resolutions. Specifically, we use the Karhunen-Loève Expansion to define the regionalization error so that the ecological fallacy is minimized. The contiguous regionalization is done using the minimum spanning tree formed from the spatial locations and the data. Then, regionalization becomes similar to pruning edges from the minimum spanning tree. The methodology is demonstrated using simulated and real data examples.
Supplementary material
Supplementary MaterialThe supplementary material includes the following files: (1) README: a brief explanation of all the files in the supplementary material; (2) The synthetic dataset; (3) The real-world dataset; (4) Code files; (5) Images used in the paper; (6) A miscellaneous example of KLE computation directly from covariance matrices.