Map Layers

The Maps app for Android works by displaying Google Maps information as a series of information-layer overlays. If you’re familiar with Google Earth, it works the same way. You can turn these layers on or off individually by following these steps:

1. Tap the Layers button to see some of the available layers, as shown to the right. This list may also scroll.
2. Tap the More Layers button to see even more layers.
3. Tap each layer to toggle it on or off. You can turn on more than one of these layers at a time.

Traffic

Much of the information on Google Maps comes from contracts with third parties, and the traffic information is no exception. Traffic information is only available for large cities, and it’s shown by color-coding the roads. Green indicates smooth traffic, yellow indicates delays, and red indicates major snarls. Traffic information can change rapidly, so don’t expect absolute accuracy. It’s also difficult (and dangerous) to check this while you’re actually on the road. Google’s Navigation feature automatically compensates for typical daily congestion patterns. For example, the directions it provides will have you use alternate routes during rush hour.

Satellite

Satellite info comes from third-party and Google-owned image sources, and those photos are stitched together and superimposed on the map information (see the example shown to the right).

The images are usually great, but sometimes the stitching process distorts the image. Consequently, there are times when an address appears to be in the wrong location, and you’ll notice patches of ground with different image quality.

Satellite images are not typically recent, and the photos for any given area could be several years old. Google will often buy new images when something major happens in an area, such as Hurricane Katrina or the earthquake and tsunami in Japan; however, don’t be surprised if the satellite image of your house doesn’t include your recently built garage.

Google Labs Layers

Google Labs is a collection of experimental features you can turn on and off (see the figure to the right). They’re not always reliable, and they don’t always last; however, some Google Labs “graduates” have turned into solid and popular features, such as the public transportation directions in Google Maps.

Most significant Google products have their own set of Google Labs experiments, but often those features won’t work on your phone (this is true for many Gmail features). Google Maps is an exception to this. Follow these steps to access the Google Labs features in Google Maps:

1. Press the Menu button while in Google Maps.
2. Tap Labs.
3. Tap individual layers (i.e., additional Google Labs features for Google Maps) to toggle them on or off. You can enable or disable layers at will.

Google uses the relative popularity of Google Labs experiments as one factor in determining what stays and what goes. A Google Buzz layer was recently axed, but there’s currently a Measure layer for quickly measuring distances between two locations. It may be replaced with something else by the time you read this.