• Started after the O'Reilly  Where 2.0 conference on June 29-30, 2005
  • Motivated by MetaCarta's business needs
  • Went through several internal revisions
  • Final rewrite took only a month
  • Released before  Where 2.0 on June 13-14, 2006

Prehistory

Cartography or map making dates back to prehistoric times. Wikipedia provides a  history of cartography. Computerized geographic information systems (GIS) were pioneered in the 1960s and 1970s (see Wikipedia on  GIS). Soon after the World Wide Web was introduced in the early and mid 1990s, web mapping interfaces started to appear. They typically showed a single map image that was reloaded from a web server after the user clicked to zoom or pan. Panning was implemented either as recentering by clicking on the map image, or by moving one step (half the map size) in one of eight directions (N, NW, W, SW, S, SE, E, NE). Some early names are the  Xerox PARC Map Viewer (launched in June 1993, now deactivated), MapBlast (acquired by Microsoft in 2002, closed down and integrated into MSN maps), and  MapQuest. The art of adding such pre-2005 web interfaces to pre-web GIS systems using open source software is documented in the book by Tyler Mitchell,  Web Mapping Illustrated : Using Open Source GIS Toolkits (O'Reilly, June 2005). Prime names in pre-web open source GIS are MapServer and GDAL/OGR.

On February 8, 2005, Google Maps was first announced. This novel web mapping application introduced continous panning by dragging. The map consisted of many small image "tiles" and the web page used JavaScript to request new tiles as needed (on demand) from the web server, without reloading the entire web page. Zooming in or out still required all tiles to be replaced, but the surrounding web page wasn't reloaded. In addition, the visible map covered more than half of the browser window, in contrast to older web mapping applications with a small map window in a large web page. Google also allowed scripting, so users could put Google's maps on their own websites and mix Google's maps with their own data. The latter became known as "mash-ups", a major component of the so-called "web 2.0" development. It was a revolution that over night made previous web maps look dated.

Just like many dreams and ideas and less successful approaches predate Wikipedia in creating a free encyclopedia on the Internet, there have also been early attempts in collaborative mapping. So far, none has been more successful than  OpenStreetMap, founded by Steve Coast in the summer of 2004. Even though it got a slow start and initially used a simple "pre-2005" web mapping interface, it has proven to scale and improve beyond imagination. Major improvements were made during 2006.

Publisher Tim O'Reilly coined the term "web 2.0" by organizing the "Web 2.0 conference" on October 5-7, 2004. This term attempts to summarize some new developments on the Internet, as it tries to recover from the the dotcom crash a few years earlier. After the advent of Google Maps in February 2005 and the enthusiasm it arose, O'Reilly organized a Where 2.0 conference on June 29-30 the same year.

Beginning of OpenLayers

Apparently, the first Where 2.0 conference inspired MetaCarta to implement an open source software equivalent to Google Maps. A rewrite was made by a group of MetaCarta employees, in the spring of 2006 and OpenLayers was first released before the second Where 2.0 conference, which took place on June 13-14, 2006.

In November 2006, OpenStreetMap introduced a "slippy map" based on OpenLayers.

In October 2007, the first release of a  Slippy Map MediaWiki Extension was announced. Wikis based on the open source software originally developed for Wikipedia can install this extension and give their users access to a <slippymap> tag for the inline display of zoom-and-pan maps.