gridmappr: an R package for creating small multiple gridmap layouts

Abstract

We present gridmappr, an R package that automates the process of generating gridmaps – small multiple data graphics of regular size, laid out with an approximate geographicarrangement. Given a set of real geographic point locations, gridmappr allocates points to a regularly-sized grid of stated row-column dimensions. This allocation is constrained such that the distance between points in real and grid space is minimised and with a parameter that affects how compactly points are allocated to the regular grid. Layout examples are presented using different parameterisations and code is demonstrated for generating complex, information-rich gridmaps using standard ggplot2.