Semiparametric Spatiotemporal Model with Mixed Frequencies R package SemiparMF version 1.0.0 Fits a semiparametric spatiotemporal model for data with mixed frequencies, specifically where the response variable is observed at a lower frequency than some covariates. The estimation uses an iterative backfitting algorithm that combines a non-parametric smoothing spline for high-frequency data, parametric estimation for low-frequency and spatial neighborhood effects, and an autoregressive error structure. Methodology based on Malabanan, Lansangan, and Barrios (2022) <https://scienggj.org/2022/SciEnggJ%202022-vol15-no02-p90-107-Malabanan%20et%20al.pdf>. Software Imports: graphics, sf, spdep, stats, utils Suggests: testthat (>= 3.0.0) Jezzu Morrisen Quimosing <mail@j3z.dev> Comprehensive R Archive Network (CRAN) Jezzu Morrisen Quimosing [aut, cre, cph] (ORCID: <https://orcid.org/0009-0001-4302-7946>) MIT + file LICENSE (https://CRAN.R-project.org/package=SemiparMF/LICENSE) 2026-02-03 application/tgz https://CRAN.R-project.org/package=SemiparMF doi:10.32614/CRAN.package.SemiparMF