I haven’t blogged about OpenStreetMap recently. Since moving to the Netherlands, my contributions to the project have slowed right down and since the import of AND data in 2007 (which “finished off” 99% of the Netherlands), I seem to have lost my motivation for all but “armchair mapping“.
But that doesn’t mean I can’t continue to be a part of the project. The main reason I fell in love with OpenStreetMap wasn’t for its ‘default’ style (called Mapnik), but for what one could do with the data. The project and the maps it produces (or helps to produce) are based around a common tagging scheme. You’re perfectly welcome – encouraged even – to take the data and produce a map that shows only the ways, areas or relations with the tags you specify; and filter out or maybe colour differently other tagged data. Maybe that’s not a very good explanation but the idea is that your map or someone else’s specialist map doesn’t have to show the map features that aren’t relevant to its target audience or to its cause.
Here’s a better example. A new style (also known as a rendering) has recently been added to the “most popular” drop-down on the main OpenStreetMap website. Out of the hundreds of renderings out there on the Internet, only four have received the privilege of becoming featured layers on the OpenStreetMap website. The latest is called Transport Map and, as its name suggests, it highlights public transport routes and stops.

The Stansted Airport area seen through Transport Map. Underlying data © OpenStreetMap.org and its contributors, CC BY-SA; tiles courtesy of Andy Allan.
Transport Map, as shown in the image of the Stansted Airport area above, shows quite clearly the area’s bus routes in red; and at high zoom levels, the line numbers of buses are printed along the route. The style also shows rail-based modes of transport as dashed black lines and as grey lines when underground (such as the tunnel under the runway at Stansted). You can also see the blue menu of the ‘promoted’ map styles at the top-left of the map in the screenshot above.
I really like the modern look of this particular style. The previous heavyweight in the public transport style arena was ÖPNV-Karte but I now find that style a little too …bulky. Do you remember when Apple changed the iTunes logo from thin green lines to thick blue ones?; I’m getting that feeling again. One can see a definite difference between the two maps’ designs if one compares them side-by-side.

Central Amsterdam on Transport Map (left) and ÖPNV-Karte (right). Map data © OpenStreetMap.org and its contributors; CC BY-SA. Map tiles © their players.
In my opinion, the more recently designed Transport Map (left) is a lot less gunky and easier to read than ÖPNV-Karte (right). I’m a stickler for clean and minimalistic graphic design, and that’s what I think the Transport Map layer offers. It begins to get more convoluted at lower and lower zoom levels but that’s the case with all map styles.
But going back to talking about including or excluding certain tags from one’s custom style(s) for a second. Note how ferries are rendered in different ways in the screenshot of Amsterdam above. There are two ferries which cross the IJ from behind Centraal Station – ÖPNV-Karte renders ferries with relations purple (like the Fast Flying Ferry which heads northeast towards IJmuiden) but not the GVB ferries; Transport Map on the other hand recognises the tag route=ferry on ways as well as relations, since both companies’ ferries appear the same. All very boring stuff, but I hope it’s a good example of how different tags produce different results – there’s still plenty of work for “armchair mappers” like me to get on with.