Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Basic method of finding geographic centre of a small country

  1. Sep 4, 2009 #1

    for a game with friends I'm trying to determine a plausible geographical centre of a small country where I will hide a treasure. My friends will need to recreate the steps I took, finding the instructions by means of a puzzle and finally receive a set of GPS coordinates, go there, find the treasure, have a barbecue there.

    How would you do that? I know there's no fixed method of determining the centre of a country. So I thought I'd use google earth as it gives me useful coordinates and as it's accessible for everyone. To simplify it even more I'll exclude all offshore territory and all islands.

    But what method is the best to use?
    printing the map, cutting out, gluing to cardboard and finding the balancing point doesn't give me any coordinates.

    Drawing many, many lines through the country is not an option as it cannot be redone by others and they might end up with different coordinates.

    As the country is roughly rectangular it should be possible to draw a box, trapeze, multiangular shape around some fixed points. And then? Draw lines from the corners will give one very rough possible result, not taking any coastline variations into account. Should I work with triangles and centroids? They might give me different results, depending on how I place the triangles but with good instructions it should be possible to redo this.

    Btw: GE does go to a place near the centre when I type in the name, but as the place is not georeferenced and as I don't know how google came to that result I don't want to use that result. Besides, where's the game in that?

    Looking for any creative ideas :)

  2. jcsd
  3. Sep 4, 2009 #2

    jim mcnamara

    User Avatar

    Staff: Mentor

    Here is something to consider:


    And there are methods, not necessarily universally agreed upon, to do this.
    You can look up the centroid method in wikipedia.

    Another method is to take the four extreme points: Northern most, Eastern most, Western most, and Southern most. Calculate the longitude of the midpoint East/West line and the latitude of the midpoint of the North/South line. The lat and long you get are a midpoint.
    Last edited: Sep 4, 2009
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook