library(SOmap)
#> Loading required package: raster
#> Loading required package: sp
SOmap()
#> Loading required namespace: rgeos

longitudes <- seq(-180, 175, by = 5)
latitudes <- approx(c(-48, -88, -48), n = length(longitudes))$y
SOplot(longitudes, latitudes, pch = 1:25)
#> No projection provided, assuming longlat

^{Created on 2019-03-20 by the reprex package (v0.2.1)}