## ---- echo=FALSE, include=FALSE-----------------------------------------------
library(knitr)
opts_chunk$set(fig.width = 5, fig.height = 5, fig.cap='',  collapse = TRUE)


## -----------------------------------------------------------------------------
library(geosphere)
pol <- rbind(c(-120,-20), c(-80,5), c(0, -20), c(-40,-60), c(-120,-20))
areaPolygon(pol)
perimeter(pol)


## ---- geo18-------------------------------------------------------------------
plot(wrld, type='l', col='grey')
a = randomCoordinates(500)
points(a, col='blue', pch=20, cex=0.5)
b = regularCoordinates(3)
points(b, col='red', pch='x')