Comet for the World Bike Tour

by Alessandro AlinoneJanuary 17th, 2011


A couple of months ago I was contacted by Luís Jorge Gonçalves, a teacher of Geographic Information Systems at Polythecnical School (ESTGA) of Aveiro University, in Portugal, who had just taken contact with Comet technology. He wrote:

The reason for this is that the World Bike Tour organizers asked us to make an application to show on a map the position in real time of a simulation of the distance traveled by the sum of the distance of 12 bikes. So, the problem was to take the distance (linear measure) traveled by the bikes (showing in real-time in a browser) and convert to 2D and 3D position. So, I would need certainly (for the sensation of continuous movement) to adopt Comet.

The web page could have a peak (in a day) of accesses of 100,000 visitors. I would like an update frequency between 1-3 seconds and I have to have access to only one field stored in a database. Lightstreamer could handle this, and if it can, which configuration I would need (CPU, bandwidth, etc.) and which version?

My answer was enthusiastic, as I love seeing new application domains take benefit from Comet and data push technology in general. I proposed to Luís that he use Moderato for this project, the free edition of Lightstreamer, because one update/sec should be enough for this kind of application.

I didn’t hear from Luís until December 28th 2010, when he gave me a short update:

As you may remember, the problem was to simulate a tour visiting some cities in the world, fed by a group of twelve bikes that are standed in a Hall in São Paulo, Brasil. The simulation will start at 12.30 on 31 December (São Paulo time). The event will have a duration of 26 days and they must “travel” about 82,000 km (so it will be a 24 hour event during 26 days).

The event will have this web page and another stand-alone web page version (with Lightstreamer web server), only for displaying in the Hall.

I used Lightstreamer to feed JavaScript code to transform the distance in 2D and 3D position (given an initial path, from the selected cities). I couldn’t simulate too many concurrent accesses to the web page, but I trust that this will be working very well!

Finally, a couple of days ago Luís contacted me again to let me know that the application is up an running and publicly visible.


Go to before January 25th, 2011. Click on “Iniciar Posicionamento“, then click on “Ativar centrar automático“. Some telemetry information on the bike should start streaming in the green box. The coolest part of the application, in my opinion, is the real-time tracking done on Google Maps (2D) and Google Earth (3D) at the same time.

I asked Luís to provide some background technical information on this:

The “26 days Tour Around the Word” is an event included in the São Paulo World Byke Tour, involving almost 7,000 participants (numbers of 2010). This year the organizers wanted to include an application in their web page that could show in a map the “position” of 12 bikes in a previously defined line (connecting selected cities in the world) and, at the same time, allow web visitors to interactively visit points of interest in the World. The obvious choice was to use Google Maps and the recent Google Earth APIs to portray the Geographic component in the Web arena. The biggest problem faced was how to deal with the expected number of concurrent accesses; using “normal” Ajax requests would involve traffic in both ways (browser< ->server) and, with so many concurrent users, transferring files (XML and KML) was not the best solution to tackle this problem. Our investigation led us to Comet technology, which could solve our objective of serving data (in this case, distance stored in a database) in only one direction (”Comet way”…). Balancing the few existing choices (mainly in terms of consolidated applications, support and clients) we have chosen Lightstreamer. Please visit also to see another version of the application in action, on the monitors at the Hall of the “26 days Tour Around the Word” event.

I surfed their web site to understand more about this project and I would like to share some information I found about their mission:

The project “Around the World in 26 Days” is part of the green development plan assumed by Mega Project World Bike Tour. Because the world needs caring for the environment and because we are concerned about the environmental future of the planet, every day we observe and implement ideas and projects that help reduce our ecological footprint.

With the project “Around the World in 26 Days” is intended to demonstrate that the simple act of pedaling can generate clean energy.

12 Bikes are installed and allow the count of miles. Wanting to cover all continents and some reference points, they will travel approximately 80,000 km. All the energy expenditure of the event will be generated by the bikes themselves, together with photovoltaic panels and towers for wind energy production mounted for the purpose.

From a technological perspective, this is another good example of the great fit of Comet for telemetry applications, as previously discussed.

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