Geographic Midpoint Calculator
Finds the geographic halfway point between two or more places. Find your personal center of gravity--the geographical average location for all of the places you have lived in. See the results on a Google Map. Using the calculator
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The new online tool Let's meet in the middle finds the ideal restaurant or other point of interest halfway between two or more addresses. Meet your friend halfway for lunch.
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Other GeoMidpoint tools
Let's meet in the middle
This free tool finds the ideal restaurant or other point of interest halfway between two or more addresses. Meet your friend or business acquaintance for lunch.
Random Point Generator
The Random Point Generator generates one or more points at random locations on the surface of the earth. You can throw one or more virtual darts at a Google map and see where they land at.
What to use it for
Some possible uses for the calculator:
- Find your personal center of gravity. Select all cities or addresses where you have lived, then view those places on a map along with a marker pointing at your exact average location.
- Find the halfway point between two cities or addresses. For example, the point that lies halfway between Chicago and Los Angeles is located 22 miles (35 km) southwest of Limon, Colorado.
- Find the midpoint of an airline flight between two cities.
- Trip planning--find a central hub for places you are going to visit.
- Find a center location for a convention or family reunion that will be fair and equitable for those who are traveling.
- Find a central place for a new business or facility that will serve surrounding population centers.
- Find latitude and longitude for millions of cities, towns, and addresses worldwide.
- Midpoint locations can be visited using GPS devices. Please read these GPS guidelines before you start your trip.
Using the midpoint calculator
Add each of your locations into the 'Your places' list one by one. See Help for detailed instructions.
You can use 'search for place' to find each of your cities or addresses. Example searches:
350 Fifth Ave, New York, NY
Atlanta, GA
London, UK
As an alternative to 'Search for place' you can select cities from one of six geographical regions or use 'Specify latitude and longitude' to enter the latitude and longitude for any location.
Personal center of gravity
You can use 'Time in location' to weight your places by time for the personal center of gravity calculation. Enter the amount of time you have spent in each place. If you leave the years, months, and days boxes blank then all of your places will be weighted equally for the calculation. The calculated midpoint will be your personal center of gravity.
As an alternative, you can use 'Weight' to enter population or other weighting factors for each location.
Besides 'Geographic midpoint', the calculator gives you two other Calculation methods, 'Center of minimum distance' and 'Average latitude/longitude'. There are reasons for choosing one method over another.
How it works
The calculator calculates the geographic midpoint based on the assumption of a spherical earth. The geographic midpoint for any two points on the earth's surface is located halfway along the great circle route which is the shortest route that runs between both points, and would be like stretching a string between the two points on a world globe then finding the middle of the string. The geographic midpoint for three or more points on the earth's surface is the center of gravity (center of mass or average location) for all of the points.
To help visualize the concept of center of gravity, imagine that a small weight is positioned at the location of various cities on a world globe. Now imagine that the globe is allowed to rotate freely until the most heavily weighted part of the globe is pulled by gravity until it is facing downward. The lowest (and heaviest) part of the globe is the center of gravity and the geographic midpoint for all of the weighted cities. See Calculation methods for a detailed description.
Map projections
A lot of distortion occurs when the earth is projected onto a flat surface, for instance, a map using the Mercator Projection. Because of this distortion, if you plot two points on a flat map along with the corresponding calculated midpoint, you will find that the midpoint is often far out of alignment with the two points. This can be easily illustrated by an example. If you place a ruler on a flat wall map between Phoenix, Arizona and Kabul, Afghanistan, the midpoint for the two cities will appear to be in the Atlantic Ocean a few hundred miles off the tip of Portugal. However, the Geographic Midpoint Calculator gives the true midpoint coordinates of latitude 88°57'N 172°57'W, which is 72 miles (116 km) from the North Pole. You can verify this by stretching a string between the two cities on a world globe.
In general, a true midpoint in the Northern Hemisphere will be farther north than you might expect it to be when viewed on a flat map, and conversely, a true midpoint in the Southern Hemisphere will be farther south than you might expect it to be. For cities that are close together this apparent difference between a spherical earth and a flat map is only slight, but the difference can be great for cities with a lot of longitude separation, such as cities on different continents. Also, there tends to be More distortion in the polar regions than near the equator. So if your calculated midpoint is farther north than you expect it to be, this is the explanation. Usually, if you take a look at a world globe it will begin to make sense.
Miscellaneous
The data used for the calculations comes from various Sources. GeoMidpoint does not guarantee the accuracy of the data.
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