library(mapproj)
## Loading required package: maps
## 
##  # ATTENTION: maps v3.0 has an updated 'world' map.        #
##  # Many country borders and names have changed since 1990. #
##  # Type '?world' or 'news(package="maps")'. See README_v3. #
map(database= "world", ylim=c(45,90), xlim=c(-160,-50), col="grey80", fill=TRUE, projection="gilbert", orientation= c(90,0,225))
lon <- c(-72, -66, -107, -154)  #fake longitude vector
lat <- c(81.7, 64.6, 68.3, 60)  #fake latitude vector
coord <- mapproject(lon, lat, proj="gilbert", orientation=c(90, 0, 225))  #convert points to projected lat/long
points(coord, pch=20, cex=1.2, col="red")  #plot converted points
lines(coord, col = 'purple')