Tuesday, October 18, 2011

3D buildings as Landmarks in Mobile Maps

Maps and City Navigation: Today I’m going to be looking at ways of including buildings as landmarks for user’s trying to navigate an urban landscape.  How important are landmarks for navigation and recall?  its relevant that memory champions who can memorize the sequence of a deck of cards in a minute use spatial landmarks as a system to aid their recall:  The memory palace technique has the user walking through a building well known to them imagining vivid tableaus such as a moonwalking Einstein (the title of an excellent book on memory) happening in different rooms.  The technique taps into our spatial memory system and shows how powerful landmarks can be. 

Google’s 3D buildings as Landmarks:  As an example I really like google's 3D buildings in google maps (see above, bottom screen shot). In a city scape the buildings can carry important landmark information for users trying to orient themselves using a map on a mobile device. A 'you are here' marker from GPS readings can make such orientation irrelevant but cities can cause a GPS trouble because of the 'urban canyon' effect so landmarks are still important.

You could choose to put full color 3D buildings onto a mobile device map as landmarks but this has issues that are useful to consider: 
  1. Device processing time: full color models would slow the device down, the data bandwidth needed is very demanding. 
  2. Visual processing: full color 3D can be complex for the user to process cognitively, for instance the color and structure of the buildings would make it more difficult to see the road pattern below.
  3. Bird’s eye View:  For way finding, the bird’s eye view of a building is often not its most salient feature visually.  It is often the view from the pavement (sidewalk for US readers) like the colorful facade of the building or the grand doorway that provides the memorable image a user can latch onto (see top part of image above which relates to the location shown on the map).  
Google’s gray, plain rendering of buildings in 3D is a good solution to the first two issues but fails on the third.

Interesting 2D Alternative: Another way of including buildings in maps so they can be used as landmarks is to use photos.  A photo of an interesting building from road level at a node (road junctions or other important route points) mimics streetview functionality but pulls out the best landmark features of the view at that node (see top part of the image above which is taken from the streetview image of the map below). When a user trying to navigate a city reached such a junction and had a choice of routes she could locate herself using the building photo.  IMHO this addresses the three problems listed above but unfortunately it introduces another issue:  what makes a good visual landmark requires human input whereas Google’s gray building layer can be produced automatically.

    Interesting 3D Alternative:
    A second alternative is to move into sub 3D view as illustrated above. Selected buildings at nodes are shown, they are rendered in gray at an enlarged scale (from a post by Digital Urban )

    If you follow the link to the post you can also see the image placed into a zoomable Google Maps interface but at a 45 degree angle, this has a lot of potential for navigation but it has issues:
      • Plan View: A plan view is better for viewing roads
      • Single Direction View: You can only see the building from one compass angle direction (North Eastwards in the above image).  Often from ground level it’s a street level feature like a large doorway that is most salient to the viewer.  Unlike features such as the Gherkin (the torpedo building in the above image) a model of a doorway doesn’t make any sense viewed from the wrong direction.  
      Usability of 3D maps in Navigation:  Related to our discussion of 3D in navigation, the comments on this post of mine about a 3D map of Southampton University's campus are interesting:  they suggest that 3D may be causing usability problems for those who are not familiar with maps .

      Conclusion: Google have to provide a base map for any journey that their journey planner may suggest to a user that works on a mobile device.  Overall, I think their current solution is arguably the best given the need to produce their maps automatically and addressing the three issues I list above.  Where it would be worth trying out the alternatives I've suggested in this post would be a map for a particular route e.g. a map informing people how to get from a particular train station to a museum.

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