Place Locator

This tool helps you find the coordinates of a place with a reasonable level of precision. Simply adjust the bounding box so that it is within the boundary of the place you wish to locate, and the coordinates displayed are good enough to locate that place. Any decimals beyond that are meaningless and useless.

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Location:

Latitude:

South North Smaller Larger

Longitude:

West East Smaller Larger

To find a location, enter the place name or address above. Or enter the longitude and latitude. Use the links above to move and resize the bounding box. The map will follow the box. (After searching for a location, the bounding box is usually too small to see.)

Much of the coordinate data on the Internet gives six decimals of precision. But does that really make sense? What does it mean to say the location of a city or entire country is this spot, give or take two inches? Yes, those points are often calculated as the centroid of the boundaries of the place, so they have mathematical meaning. But in human terms, does it really mean anything to say that China is here, rather than a few feet (or miles) to the left?

A quick search turned up these answers for the location of France:

Which of those is correct? Well, all of them, because they are all points within France. But the ones with more decimals are not more correct than the others. Even with no decimals, there are a large number of coordinates that lie within France. The choice is arbitrary, though I tend to like (47, 2) since it is roughly centered. But NOT (47.000000, 2.000000), which introduces artificial and meaningless precision.

As you play with this tool, you will notice that for most countries, zero decimals (+/- about 35 miles) is more than enough precision. Larger countries only need what I display as "-1 decimals" (where the last digit is always 0, or +/- about 350 miles). For example, (40, -100) is more than adequate to locate the United States.

Generally, two decimals (+/- about 0.35 miles) is good enough for cities, such as (58.14, 8.00) for Kristiansand, Norway. Notice in this case that the trailing .00 is necessary precision, but any additional zeros would be pointless. Some larger cities can be located with just one decimal (+/- about 3.5 miles), but you have to be careful. Often that larger box indicates not just the city, but the metropolitan area, including a number of neighboring towns.

Some small towns, such as those that have become neighborhoods of a large city, might need three decimals (+/- 180 feet) to distinguish from their neighbors. Though I haven't yet found a good example of this. And four decimals (+/- about 18 feet) should be quite good enough to locate your house.

In fact, GPS units are only accurate to about five decimals on a good day. At other times, they are only good to about four decimals. And on bad days (or under trees or near tall buildings) they might be only good to about three decimals. So just because they tell you where you are standing with a six decimal number doesn't mean it's right. Stand there and watch it for a while, and you'll see that the last digit or two are meaningless.

(Note that the change in precision due to adding or removing a digit is dependent on the numbering system in use. This tool uses decimal degrees, so adding or removing a digit changes the precision by a factor of 10. A similar tool that used degrees, minutes, and seconds would have a little different behavior. Changing from degrees to tens of minutes, or minutes to tens of seconds, would change precision by a factor of 6, while the other digits would still be a factor of 10.)