There’s a really interesting article in The New York Times about the proliferation of tools on the web that allow individuals to create and add information to maps. Google Maps and Google Earth are probably the most prominent examples of the tools available, but there are others as well. The article focuses on how people all around the world are contributing and collaborating on maps.

The article does not mention that much the other really amazing aspect of this technology: the ability to visualize historical change through map overlays. “Google Earth in 4D” is the shorthand for one version of this, which was developed by the David Rumsey Historical Maps Collection. The David Rumsey Collection took some of their historic maps and provided them as overlays in Google Earth, so it’s possible to overlay a city map of London from 1843 on the Google Earth representation of present-day London.

Apart from the new wealth of information being created by amateur cartographers using these web tools to map the present-day world, I think there is obviously huge potential for use by historians as a supplement to their research as well as to enhance their teaching.

‘What is happening is the creation of this extremely detailed map of the world that is being created by all the people in the world,’ said John Hanke , director of Google Maps and Google Earth. ‘The end result is that there will be a much richer description of the earth.’

This fast-growing GeoWeb, as industry insiders call it, is in part a byproduct of the Internet search wars among Google, Microsoft, Yahoo and others. In the race to popularize their map services - and dominate the potentially lucrative market for local advertising on maps - these companies have created the tools that are empowering people with minimal technical skills to do what only professional mapmakers were able to do before.

‘It is a revolution,’ said Matthew Edney, director of the History of Cartography Project at the University of Wisconsin at Madison. ‘Now with all sorts of really very accessible, very straightforward tools, anybody can make maps. They can select data, they can add data, they can communicate it with others. It truly has moved the power of map production into a completely new arena.’

The complete article from The New York Times: “With Tools on Web, Amateurs Reshape Mapmaking”