Networks in Space, Mark Newman, netsci0821 Dec 2008 in
Mark Newman, Networks in Space,
This is about networks in geographic space.
Mark is looking at properties of networks that are tied to geography.
Transport networks are a good example, and we are looking at the
difference between road and air networks.
The road and air networks are very different, even though you use both
of them for getting from A to B.
There is different bahviour, could I say 'driving' the use of these
networks. For roads we want to minimze the length of our journey, but
that's not such an important factor in flight journeys. When we fly we
like to take direct flights, and minimize the number of flight hops that
If you model this behviour you get out networks that look a lot like
road and flight networks.
Their first model looked at connecting randomly distributed nodes.
In order not to get influenced by population density they made a map
that is rescaled by population density. This is called a cartogram.
You can see some really nice election cartograms that Newmann and
Gastern made here: http://www.cscs.umich.edu/~crshalizi/election/
There is a really nice historical example from Raisz from the
Geographical REview from 1943.
It looks like most recent attempts have been hand-drawn, but they look
Newman and Gastner made a difffusion algorithm that allows you to do
OK, it looks like this started off as a network talk, but segwayed into
a demo of this mapping technique. Ahh, no, we are back to looking at
The interesting result from this talk is that the best covering fro
utilities such as airports or post offices does not grow lineraly with
popultaion, but to the power of 2/3.
This was also a pretty nice talk.