Procrustes-based analysis of ET time series (raster-based)

This repository provides R code to perform a pixel-wise Procrustes Analysis of decadal evapotranspiration (ETIa) time series derived from FAO WaPOR data. The workflow starts from multi-temporal raster stacks of decadal ETIa and estimates spatially varying rotation, anisotropic scaling, translation, and fitting error parameters with respect to a reference seasonal ETIa profile defined as the pixel-wise median.

The method is implemented using a Singular Value Decomposition (SVD)–based solution, ensuring orthogonality of the rotation matrix and robustness against ill-conditioned systems. All Procrustes parameters are exported as GeoTIFF raster layers, enabling direct spatial analysis and visualization of seasonal ETIa dynamics in GIS environments.