GPS: How to

GPS stands for "Global Positioning System." If you want to geek out on how the whole thing works, you can start here.

If you use a GPS device (even in your phone) or Google Earth, you won't need this guide. Just use the coordinates given.

We have given you a "click here" option so you can see the location in the Google Maps satellite view. Use the controller in the top-left of the image to zoom in or out, and click your mouse to "grab" the image and move it. No download necessary.

You can find any coordinates in Google Maps without special equipment or downloads.

Just follow these three easy steps:

1. Go to www.google.com
2. Click the "Maps" link at the top of the page.
   (If you're clever, you can combine these two steps by going to http://maps.google.com)
3. Put the coordinates in the search window on the page and click "Search Maps."

You're there! If you see a blank, click the "Satellite" tab in the top right of the map window.

(Google has not mapped China in English yet; all you can see is a satellite image with no labels. There are third-party maps in Chinese--without GPS support--at http://ditu.google.com)

Try it with these coordinates for Shenzhen's City Hall:

22 32 47.70, 114 3 16.82
22.546583, 114.054672

Remember, use one line or the other, but not both.

If you want to try Google Earth (or need Google Earth help), start here.

A little more about the coordinates:

We have given them in two forms.

The first is the "DMS" (Degrees, Minutes, Seconds) form.

In this system, Shenzhen's City Hall is at 22 degrees, 32 minutes, 47.70 seconds north and 114 degrees, 3 minutes, 16.82 seconds east. This is more conveniently expressed as 22° 32' 47.70"N, 114° 3' 16.82"E. Note that Google Earth and Google Maps will take this without the symbols, as we have expressed it. Put this into the Google Maps page:

22 32 47.70, 114 3 16.82

The second way is called "Decimal Degree" or "degdec," where the 60 minutes in a degree and 60 seconds in a minute have been converted into a single number, which is the degree and its fraction expressed as a decimal. Here City Hall is expressed this way:

22.546583, 114.054672

We have given both systems because some GPS units allow only one or the other, and some users favor one over the other. We aim to please.