Getting started with priogridR • priogridR

priogridR provides utilities and general spatial converters for PRIO-GRID. The package delegates grid construction, configuration, and core raster alignment to the official priogrid package while providing a consistent pg_ interface for common input formats.

library(priogridR)

Grid identifiers

PRIO-GRID identifiers start in the south-western cell and increase eastward, then northward. The matrix returned by pg_create_indices() is displayed with the northernmost row first:

pg_create_indices(nrow = 3, ncol = 3)
#>      [,1] [,2] [,3]
#> [1,]    7    8    9
#> [2,]    4    5    6
#> [3,]    1    2    3

Neighboring cells

pg_neighbors() returns queen-contiguity neighbors: cells sharing an edge or corner. Longitude wraps across the antimeridian by default, while latitude does not wrap across the poles.

pg_neighbors(5, nrow = 3, ncol = 3)
#> [1] 7 8 9 4 6 1 2 3
pg_neighbors(1, nrow = 3, ncol = 3)
#> [1] 6 4 5 3 2

For a grid that should not wrap longitudinally, use:

pg_neighbors(
  1,
  nrow = 3,
  ncol = 3,
  wrap_longitude = FALSE
)
#> [1] 4 5 2

Reproducible data paths

pg_paths() constructs conventional project paths without changing the working directory:

pg_paths(root = tempdir())
#> $root
#> [1] "/tmp/RtmpxdVcGe"
#> 
#> $raw
#> [1] "/tmp/RtmpxdVcGe/data/raw"
#> 
#> $processed
#> [1] "/tmp/RtmpxdVcGe/data/processed"
#> 
#> $temporary
#> [1] "/tmp/RtmpxdVcGe/data/temp"

Pass create = TRUE when the directories should be created.

Conversion results

Conversion functions can return:

a data frame with return = "data";
a terra::SpatRaster with return = "raster"; or
a pg_result containing data, raster, and metadata with return = "result".

Use pg_write_result() to save supported tabular or raster outputs. See the conversion-workflows vignette for format-specific examples.

Plot styling

pg_theme() supplies a minimal map-oriented ggplot2 theme:

ggplot2::ggplot(
  mtcars,
  ggplot2::aes(x = hp, y = mpg)
) +
  ggplot2::geom_point() +
  pg_theme()