Build Potentiometric Surfaces and Hydraulic-Gradient Arrows R package potentiomap version 0.2.0 Prepares groundwater-level observations from measured hydraulic head or from depth-to-water and land-surface elevation, interpolates potentiometric surfaces using thin-plate splines, inverse-distance weighting, ordinary Kriging, universal Kriging, or user-supplied methods, and creates raster, contour, diagnostic, support, and hydraulic-gradient products for review and export. Functions retain method conditions and fit diagnostics, validate explicit prediction tasks, inspect model-conditional uncertainty and monitoring-network sensitivity, identify limited prediction support, and check whether scaled hydraulic-gradient arrows remain within finite raster support and end at lower modeled head. Raster processing uses methods from 'terra' (Hijmans 2025) <doi:10.32614/CRAN.package.terra>, thin-plate splines use methods from 'fields' (Nychka et al. 2021) <doi:10.5065/D6W957CT>, and geostatistical interpolation uses methods from 'gstat' (Pebesma 2004) <doi:10.1016/j.cageo.2004.03.012>. Software Depends: R (>= 4.1) Imports: fields, grDevices, graphics, gstat, sf, stats, terra, xml2 Suggests: knitr, rmarkdown, testthat (>= 3.0.0), withr Elvin Cordero <elvin.cordero@seamountgeo.com> Comprehensive R Archive Network (CRAN) Elvin Cordero [aut, cre] (ORCID: <https://orcid.org/0009-0003-8025-283X>) GPL-3 2026-07-18 application/tgz https://CRAN.R-project.org/package=potentiomap doi:10.32614/CRAN.package.potentiomap en-US