Find first-order PRIO-GRID neighbors

Returns queen-contiguity neighbors: cells sharing either an edge or a corner with the requested cell. Longitude wraps across the antimeridian by default; latitude never wraps across the poles.

Usage

pg_neighbors(x, nrow = 360L, ncol = 720L, wrap_longitude = TRUE)

Arguments

x

One PRIO-GRID cell identifier.

nrow

Number of grid rows.

ncol

Number of grid columns.

wrap_longitude

Should the western and eastern edges be adjacent?

Value

An integer vector containing neighboring cell identifiers. Interior cells have eight neighbors and cells in the northern or southern row have five when wrap_longitude = TRUE.

Examples

pg_neighbors(234209)
#> [1] 234928 234929 234930 234208 234210 233488 233489 233490
pg_neighbors(1, nrow = 3, ncol = 3)
#> [1] 6 4 5 3 2