Google Maps (for a time named Google Local) is a free web mapping service application and technology provided by Google that powers many map-based services including the Google Maps website, Google Ride Finder and embedded maps on third-party websites via the Google Maps API. It offers street maps, a route planner for bicycles, pedestrians (routes less than 6.2 miles) and cars, and an urban business locator for numerous countries around the world.

A related product is Google Earth, a stand-alone program for Microsoft Windows, Mac OS X, and Linux which offers more globe-viewing features.

Satellite view

Google Maps provides high-resolution satellite images for most urban areas in Canada and the United States (including Hawaii, Alaska, Puerto Rico, and the U.S. Virgin Islands) as well as parts of New Zealand, Australia, Egypt, France, Germany, Greece, Hong Kong, Hungary, Iran, Iceland, Italy, Ireland, Iraq, Japan, Jordan, Taiwan, the Bahamas, Bermuda, Kuwait, Mexico, the Netherlands, the United Kingdom, and many other countries. Google Maps also covers many cities including Moscow, Istanbul, and most of India.

Various governments have complained about the potential for terrorists to use the satellite images in planning attacks. Google has blurred some areas for security (mostly in the United States),Fact: date=August 2007 including the U.S. Naval Observatory area (where the official residence of the Vice President is located), and until recently ,Fact: date=August 2007 the United States Capitol and the White House (which formerly featured erased housetop). Other well-known government installations are visible including Area 51 in the Nevada desert.

With the introduction of an easily pannable and searchable mapping and satellite imagery tool, Google's mapping engine prompted a surge of interest in satellite imagery. Sites were established which feature satellite images of interesting natural and man-made landmarks, including such novelties as "large type" writing visible in the imagery, as well as famous stadia and unique earth formations.

Although Google uses the word "satellite", most of the high-resolution imagery is aerial photography taken from airplanes rather than from satellites.

Implementation

Like many other Google web applications, Google Maps uses JavaScript extensively. As the user drags the map, the grid squares are downloaded from the server and inserted into the page. When a user searches for a business, the results are downloaded in the background for insertion into the side panel and map - the page is not reloaded. Locations are drawn dynamically by positioning a red pin (composed of several partially-transparent PNGs) on top of the map images.

The technique of providing greater user-interactivity by performing asynchronous network requests with Javascript and XMLHttpRequest has recently become known as Ajax. Maps actually uses XmlHttpRequest sparingly, preferring a hidden IFrame with form submission because it preserves browser history. It also uses JSON for data transfer rather than XML, for performance reasons. These techniques both fall under the broad Ajax umbrella.