Take Web 2.0, mix liberally with local maps from across the United States or the world, and add information on restaurants, hotels, gas stations, real estate, or dozens of other potential sources. The result is among the hottest and most useful new generation of applications on the Web--the location mashup.

More than 35,000 location mashups--ranging from restaurant locators to celebrity trackers--have been created using Google Maps alone. Want to know where Madonna has been hanging out? Go to www.gawker.com/stalker, where you can get daily updates on the whereabouts of celebrities, with exact locations plotted on a map. Like much of Web 2.0, location mashups are the province of creative problem solvers who develop them independently. Some businesses have created their own, but many are a step behind the trend.

(click image for larger view) BP's hurricane-warning mashup combines weather, pipeline, and ocean data

Mashups rely on Web 2.0 development technologies--Ajax techniques and Adobe's interactive Flash software, for example--so they function more like interactive software than a static Web page. The user experience can include panning and zooming over a map or aerial view of Earth; fine-detail maps that appear in small, secondary windows; and other types of dynamic information associated with the points on the map. Mashups typically reuse data and services from other Web sites and Web applications, and they can be created by people who aren't professional developers. Since they're assemblages of existing data and services, simple mashups generally don't require a lot of additional coding.

New tools to build location mashups are emerging. Yahoo this month released Pipes, an experimental service that lets you remix data feeds and create data mashups in a visual programming environment. A drag-and-drop editor makes it possible to connect multiple Web data sources. Pipes supports GeoRSS--an RSS feed of location information--and the output can be displayed on Yahoo Maps as well as other mapping applications.

Startup FortiusOne is developing a public data-sharing service, called GeoCommons, for creating map mashups. GeoCommons is still in the works. FortiusOne also has developed a service, called GeoIQ, that lets developers add geographic data visualization and analysis capabilities to online mapping applications. A beta version of GeoIQ was released in November. It includes everything from facts and figures detailing the locations of spammers by street address to the incidence of West Nile virus and cancer mortality rates and the locations of bars in New York where single women hang out.

FortiusOne describes GeoIQ as "location intelligence for the masses." FortiusOne's APIs can be used by developers to highlight data using heat maps, which use color to represent data. An enterprise version of GeoIQ APIs is available to businesses and government agencies that want to combine and analyze geographic data. The Department of Homeland Security and other agencies use GeoIQ to assess infrastructure vulnerabilities across the country.

MASHUP LAGGARDS

Some companies have developed location mashups to help customers, improve internal operations, or both. Following hurricanes Katrina and Rita in 2005, oil and gas company BP created a "hurricane management system" using Microsoft's Virtual Earth that provides employees with frequently updated views of weather patterns in the Gulf of Mexico. It draws on geographic information from ESRI Data, a widely used source in the petroleum industry, and pulls together historical data on hurricanes, plus information on pipelines, buoys, vehicles, and offices. That's all combined with RSS feeds and information from weather bureaus, oceanographers, satellite images, traffic reports, and hotel vacancies. The system uses Microsoft SharePoint Server 2007 to present layers of information on a map such as counties affected, weather patterns, and local population and other demographics.