Is it true that 3D suck?

I was on a road trip holiday the week before last and before I left I read this James Fee blog post he has an image of Godzilla walking into electricity pylons with the tag line 'Google Earth keeps bumping into things trying to work out why it is here'. This led me to ruminate and I quickly wandered from James' post about GEarth enterprise to the more general 'what is Google Earth good for?'. I considered features such as

• layer control
• zooming
• time animation

but, powerful those these are for visualisation, they are all also available in Google Maps and are just as much 2 as 3D*. What truly sets a virtual globe apart from web mapping is 3D and this is what I ended up ruminating on most of all:

Current Uses of 3D. I don't have much time for fancy graphics, so beyond cool looking 3D flights, what does 3D in Google Earth actually add to understanding at the moment? There are several examples:

• 3D buildings: Populating a city with 3D models adds a lot of value to urban geography, you can see what a skyline looks like or enhance what you've seen on a walk through a foreign city by revisiting your walk in GEarth later. 3D trees are available in GEarth too but I don't think they're nearly as useful as the buildings.
• Mountains and Valleys: When considering topics where topography is important a 3D view can add understanding. The Appalachian Mountain removal project is a perfect example as the location of the mines on the tops of the mountains is key to understanding the problem.
• Earth Science Models: 3D models of large scale processes on our planet such as subducting plate margins and hurricanes can add understanding, see the project I'm working on with Old Dominion University and others.
• Streetview and Panoramas: Streetview and gigapan panoramas come close to giving a realistic 3D view of a scene. Streetview enables you to move from location to location whilst a gigapan allows you to zoom in on interesting features of the panorama.

IMHO the Streetview/Panorama example is the most important of these. However, the 3D visualisations discussed above are far less common on the web than the uses of 2D like data mashups, real time maps and map related infographics.

Future Uses of 3D: But what is available now may not be the whole story. Can we imagine a use for 3D in the future that is the 'killer app?'. Here's some possible future uses:

• Real 3D Earth Science Models: Currently the way to present a 3D geology model is to slide it out of the ground to give the viewer the idea that its come from underground. It works pretty well but it would be good to be able to fly beneath the earth's surface and show models in their real situation.
• Thematic 3D data: I've frequently discussed 3D thematic maps on this blog, mostly unfavourably. However, the 'Obama: One People' visualisation I discuss here looks to me like it really adds something, I think 3D thematic maps could be useful visualisations but they remain unproven - no one has done user tests on them.

I can foresee that Streetview and similar panoramas will improve in time with real time 360 views and developments like Microsoft's streetslide helping make them more usable. Beyond that, neither of the topic areas listed above is convincing as a killer app.

2D Dominance: So I don't think 3D is ever going to topple 2D as the best way to visualise spatial data. This may seem a little surprising, we live, work and move about in 3D all the time, why won't 3D will become more common? What this point misses is that we also symbolise all the time too, a road map is far more useful than satellite imagery for navigating with because it strips out everything unnecessary (trees, people, greenhouses) and leaves exactly the information we need: roads and junctions as symbols. Usually the best visualisation is the simplest one possible so if a spatial problem can be visualised in 2D its best to do it that way. Especially if you are rendering the map on a small screen smart phone. We live on a planet that were it reduced to the size of a billiard ball would be smoother than any in the world so it really isn't surprising that most of our spatial data can be effectively reduced to 2D.

*of course you can now pull 3D GEarth into a Google Maps but I'm not really focussing on the technology here.