Ihave a map with surface observations (metar). i have to draw contour lines for sea level pressure using an interval of 4 hpa. i also have to mark centers of highs (h) and lows (l). i didn't get any explanantion on how to do this so i would really appreciate it if someone could me out. i don't need you to do the whole thing (unless you want to) but just a big enough chunk so i can see how to do it on my own. you. i posted a close up of the east side of the map if you want to demonstrate on that.