“…Over the last few decades the spatial statistics community has attacked this big GP problem from many fronts and offered many different and efficient solutions to ease the computational burden. Methods include sparse nearest neighbor approximations (Vecchia, 1988;Stein et al, 2004;Datta et al, 2016a), low-rank approximations (Banerjee et al, 2008;Cressie and Johannesson, 2008), sparse-plus-low-rank method (Ma et al, 2019), multi-resolutional approach (Katzfuss, 2017), data partitioning (Barbian and Assunção, 2017;Guhaniyogi and Banerjee, 2018), covariance tapering (Furrer et al, 2006;Kaufman et al, 2008), stochastic partial differential equations (Lindgren et al, 2011), composite likelihoods (Bevilacqua and Gaetan, 2015;Eidsvik et al, 2014), gridbased methods (Nychka et al, 2015;Guinness and Fuentes, 2017;Stroud et al, 2017), among others. A comprehensive review of all these methods is beyond the scope of this paper but we refer the readers to the articles Sun et al (2012); Bradley et al (2016); Banerjee (2017); Heaton et al (2019); Banerjee (2020) for reviews and comparisons of the methods.…”