I'd like to share with you some recent work I've done on visualizing
the routing table.
As the page says, I use the routeviews snapshots to create maps
showing the locations and size of each prefix in the table. The
IPv4 address space is mapped into 2-D with a Hilbert curve (as seen
on xkcd). I have maps for snapshots going back to early 2004 and
an animation that shows the evolution over time.
Is the older pictures based on older allocation data, or present-day data?
I assume you are refering to the labels showing to whom each block
is allocated? Those come from IANA's file at
http://www.iana.org/assignments/ipv4-address-space, which gives the
date (just month and year) of each allocation. I dont have
an archive of that file so to show the state of things in the past
I just change any allocation after a given date to "Unallocated".
The routing table data (the colored bits) comes from Routeviews,
which has a good archive.
BTW, one thing that really stands out if you watch the animation
is the two times (July 2005 and June 2006) where routes appeared
for large areas of unallocated space.