The point of my post isn't one demo. The module-names of the existing demos aren't really visible, instead the interface is roughly:

$ perldl
perlDL shell v1.357
[snip]
Type 'help' for online help
Type 'demo' for online demos
Loaded PDL v2.077 (supports bad values)

Note: AutoLoader not enabled ('use PDL::AutoLoader' recommended)

pdl> demo
Use:
   demo pdl         # general demo
   demo 3d          # 3d demo (requires TriD with OpenGL or Mesa)
   demo 3d2         # 3d demo, part 2. (Somewhat memory-intensive)
   demo 3dgal       # the 3D gallery: make cool images with 3-line scr
+ipts
   demo 3dtk        # Tk graphics (requires Tk)
   demo bad         # Bad-value demo (Optional: PGPLOT)
   demo cartography # Cartographic projections (Req.: PGPLOT)
   demo gnuplot     # Gnuplot graphics
   demo pgplot      # PGPLOT graphics output
   demo pgplotOO    # PGPLOT OO interface
   demo transform   # Coordinate transformations (Req.: PGPLOT)

pdl>
[download]

The point of my post was about a new PDL capability of live updating from (in this case) a websocket. The naming of a demo module for that is not something I was asking for help on ;-)

However, while it's not really entirely a Cartography thing (it's as much a 3D, and also live-updating thing - the mash-up/synergy are equally what I want to show off), the name "Thunderstruck" is so good it will definitely be involved - thank you!