january 2005 archives

Sunday, January 30, 2005

Accessible maps

Last week was an interesting time at work. Never before I had to think so much about what a web atlas actually is. What do you need to build and manage a web atlas? What important measures have to be put in place to start a new atlas from the ground up. Also, I finally got a chance to meet a Trias. He's a PhD student at ITC doing research into web atlases. He also takes a step back and tries not to get too much tied up in the technology: Flash or SVG, MapServer or Arc IMS. For Trias, it's RDF that seems to matter most!

Also this week, we had a meeting with a consultant from the Bartiméus Accessibility Foundation to see what we should and actually can do to make our web atlas accessible to people with disabilities. First of all, we really should be using web standards. After changing the character encoding, there were 77 errors on the home page alone. Nevertheless, some of the measures to overcome the accessibility issues are not only beneficial to people with disabilities, they're also of use to the average visitor. For example, have a look at the Canadian Mapping for the Visually Impaired portal that aims to make maps and geo-spatial data accessible on-line.

Thursday, January 27, 2005

Travelling in Norway? Go abroad

That's the travel directions that Microsoft Mappoint gives you upon requesting a route from Haugesund to Trondheim in Norway. Starting in Haugesund, the directions tell you to pass through the UK, France, Belgium, Netherlands, Germany, Denmark, and Sweden before delivering you in Trondheim.

All joking aside: I've been there too! I remember well getting an angry phone call from one of the directors of a British bank. Most of their board members had arrived too late for the meeting in Cardiff. The online travel directions service they'd bought from the company I worked for guided people from England to Wales all the way through Glouchester, thus ignoring the Severn Bridge altogether. After some serious going forth between data supplier and routing engine developers, we established that the data collected through separate surveying teams for England and Wales had never been matched up! Go figure...

Testing a new routing engine with the Danish route network a few years later on showed similar results. It was impossible to generate routes between some of the islands. Important connections were left out the standard data pack for Denmark and came on a separate CD-ROM from the data supplier. Typical, hey!

There doesn't seem to be any trouble generating routes from Trondheid to Haugesund though. It's a typical case of YSKA. That's a Finnish abbreviation for turn restriction and one-way street information (legacy code, indeed). A co-worker of mine informed me of this fun piece of info on the Telegraaf website.

Saturday, January 15, 2005

One million pageviews

Yeah, right. I wish! If only webmapper.net attracted that many visitors... The online Atlas of the Netherlands today sent its millionth page across the web. Next wednesday is the second meeting of the National Atlas project group. This statistic should be a great incentive to pursue our goal!

Sunday, January 02, 2005

Collaborative mapping, distributed map servers

In my presentations of the paper Collaborative mapping, I have hinted at the possibility of creating maps from GPS tracks. Going about their daily life, people collect the GPS tracks and upload them to a central facility where a map is derived from the location data. The Amsterdam Realtime project is an example that people are very keen to record their tracks if they can use and view their tracks later on. The idea seems to have caught on and is now being implemented by LondonFreeMap in collaboration with OpenStreetMap. Saul Albert also mentions the Downhill Map of Bristol by Heath Bunting in his article Crossing the line between mapping and map making. The University of Openness Faculty of Cartography are making free-of-copyright street level maps of London:

Collect GPS data
Normalise and synthesise data into real shapes
Annotate shapes with real-world semantics
1. Annotate completed map with civic and historic information
2. Find partner organisations to contribute to, and back, the project
Give everything away

On the geowanking mailing list some interesting considerations are being discussed that play a role in collaborative mapping projects:

Use a seed database, i.e. an existing database (for example TIGER) that can be updated with data collected from GPS tracks and annotations. Unfortunately, there's no such database for European countries. However, OS paper maps over 50 years old can be scanned. Digital line detection/tracing throws us back 20 odd years!
Delineate areas of responsibility. This is an interesting consideration at the beginning of the project. As the project is fully up and running, I prefer everyone can upload their tracks of any geographic area. Of course, there may be one person to moderate the submitted tracks.
Show the status of a particular feature. Again, it may be useful at the start of the project that a feature needs still to be checked and confirmed, but I'd say any feature can be updated over time as new tracks become available that contribute to the geographic description of that particular feature or that change the attributes of the feature (e.g. average travel time, directionality).

Another consideration is the amount of computation power and bandwidth to serve the data. This takes us to the next topic: distributed map servers, or distributed geolibraries. Moving from a single facility that serves geographic data of the world to many distributed geographic data stores that serve global and/or local data sets is what I termed the Gnutellasation of geographic information. Russ Nelson discusses a tile-based approach for raster images using DNS to split the work across a bunch of cooperating entities, a distributed Terraserver.

Mapping out locative media

The highly interesting Pasta and Vinegar by Nicholas Nova recently linked to the locative media issue map. The issue map shows how various locative media projects are related and share common interests, thus enabling urban gaming explosion. Gaming is seen as the perfect structure for experimenting with these new tools, places and communities.

Short descriptions and observations about many of the projects shown on the map can be found on networked performance, including the very locative media issue map. Also check out the list of links to locative media compiled by YProductions.

By the way, you may have experienced difficulties connecting to the locative media network website at http://locative.org/. The website seems to have been superseded by the Pervasive and Locative Arts Network (PLAN).