Sparse-Smooth Spatially Varying Coefficient Quantile Regression // Implements sparse-smooth spatially varying coefficient quantile regression (SS-SVCQR), combining quantile regression of Koenker and Bassett (1978) doi:10.2307/1913643, grouped variable selection of Yuan and Lin (2006) doi:10.1111/j.1467-9868.2005.00532.x, graph regularization, and the alternating direction method of multipliers of Boyd et al. (2011) doi:10.1561/2200000016. The package provides graph- regularized estimation, spatially blocked cross-validation, prediction, diagnostics, and simulation helpers for global- local spatial quantile regression.