Maps are a really powerful way to work with information, particularly in relation to transport and travel. Although there are a range of maps available for free on the internet, at best these allow you to plot your own route to a copy. In the same way that Wikipedia, a collaborative or ‘crowd-sourced’ encyclopaedia, is revolutionising knowledge, so OpenStreetMap, a crowd-sourced map, is doing the same for geographical information. The difference is like being sent a document as scanned image rather than as a file containing text. With a document sent as text you can cut and paste words, change the formatting and add to it.
Cartography, the science of map-making, is not just about accurate classification and recording of geographical data but also carefully thinking about how to display data on a map. It’s important to think about both of these elements: showing too much information can make a particular map confusing and difficult to use. OpenStreetMap enables crowd-sourcing of the classification (known as ‘tagging’) of data and complete freedom as to what data is used in a map and the style.
You can see different styles of maps on www.openstreetmap.org by clicking on the menu in the top right to see a general map, a cycling map and a public transport map. These different maps are produced from the same underlying map data. You can see how it is classified through tags on the map features page.