Day: September 25, 2014

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Fun with Turtles

Following on from my last post on running agent based models in MapTube using AgentScript, I’ve now got my “live” tube animation working:

I’ve speeded up the trains by a factor of 10 so you can see them move, but otherwise, it’s just a modification of the coffeescript code I was using before on a standalone web page. This isn’t on the production MapTube website yet, only the development tree as there are still a few problems to iron out. Also, it’s not really live as the data is loaded from an archive file stored on the same site. This highlights one of the problems with loading data dynamically. I could pull a live file straight off of the ANTS server which we use for all our live visualisations. The problem with this is that it’s a cross site request, so I’m going to need to put a JSONP endpoint into the server in addition to regular JSON and XML. The alternative would be to create a proxy on MapTube, but I’m trying to keep the code as generic as possible.

What’s happening at the moment is that the coffeescript model of the tube system is created just as though it were a normal standalone AgentScript model with no map behind it. The initialisation creates an “AgentOverlay” class which encapsulates the model and handles all the necessary interaction with the Google Map:

[code language=”js”]
overlay = new AgentOverlay ‘layers’, bounds, map, ()=>
new MyModel "layers", 5, -25, 25, -20, 20, false, false, bounds
[/code]

The “AgentOverlay” communicates with the MapTube code on the page to register the overlay which allows interaction with it. As you can see from the YouTube clip, the layers icons on the right hand side are still missing and I need to include some additional code so the model can pop up its own colour scale and other widget windows. At the moment it’s looking like it’s possible to give the code almost complete control over the information it shows, which will give me the ability to create custom maps very easily. The only issue that looks impossible to fix, though, is the separation of code between layers. There are always going to be code clashes between layers, so it’s just going to have to rely on programmers using unique namespaces for their code.