Wednesday, November 2, 2011

Streetiview vs Streetside from a users point of view

So there has been a lot of blog posts on the internets comparing Bing's Streetside with Google's Streetview.  Mostly these cover technical and privacy points:

Streetview: Much larger coverage (certainly in the UK), Full 360 degree view

Streetside:  Avoided some of the privacy controversy by targetting 'super public' areas such as city centres rather than residential areas.  Viewing is more limited to a row view of buildings that slides by.

No one has covered the usability issues in detail so I thought I'd make some observations, to do this I need to go off on a bit of a tangent into 3D virtual environments:

Less Control = Easier to Use:  I've just finished a draft of a paper in which I reviewed Google Earth Tours.  One thing I discovered in the literature is that in 3D environments (Google Earth, Second Life) the 6 degrees of freedom* that a user needs to control can cause problems of usability:
  • Walls aren't solid: Users can crash through model walls which is disorienting
  • Desert Fog: Users end up very close to a plane surface like the ground, they can't see any features to orient themselves or guess scale - they are said to be experiencing desert fog.  
  • Peripheral Vision:  Because of the limited computer window into the environment they miss visual clues from their peripheral vision that they pick up in the real world (better in a CAVE setup or similar of course) 
Limiting their degrees of freedom of movement can help users avoid these issues.   An example is a tower in Second life - if a user can be 'locked' into moving around it so they can only fly a fixed distance from the tower and their vision is locked directly towards the tower they would avoid some of the problems listed above.  Their degrees of freedom have been reduced from 6 down to 2 (they can only fly up/down outside the tower, orbit it left/right) but they can still explore it.  Even more radical in a Google Earth tour users only have VCR play/pause/rewind controls effectively reducing their freedoms of movement down to 1.  

Streetside Constrained Freedom:  Streetside has taken the same 'constrained view' approach.  They allow a user to only look directly at the side of the road, this is sensible as in a cityscape as this is the most useful view.  To switch view to the other side of the street you simply click a little 180 degrees view button which zooms you around.  Streetside:
  • Mutiple Controls: Avoids problems of having to operate multiple controls (in Streetview they may expect double clicking to zoom them into a photo view, in fact it moves their position)
  • Look Sideways: Allows users to move along a street whilst looking at buildings.  In Streetview users have to face foreward to move foreward, to look at the buildings on the side of a road they need to stop and turn.
UPDATE 3rd Nov:  Actually that's not strictly true.   Streetside offers 'slippy slides' of the street going past which is better than Streetview's click-refresh operation.  However, you can arrange Streetview so you're looking side on to the street and then click the arrows so you move along.  Its quite clever actually.   
  • Fast: Allows users to whisk along a street in a zoomed out view faster than moving through Streetview (in a little informal test I did myself, see the zoomed out view that allows this in the above screenshot )
However, this comes at a cost.  Streetview has the advantages:
  • Less Disorientation: I think its easier to become disorientated by moving down a street only looking at one side.  Certainly for testing out a cycle route across a town, Streetview is more natural and would be the better tool.
  • Photo stitching is better in Streetiview, in Streetside I noticed whole streets warped out of view.  This may be a technology issue that is solved soon but at the moment it's a real issue.
  • 3D Buildings: While looking at Streetview, Google Maps also supplies 3D building models (earlier post on this topic see screenshot above) which further helps with orientation. 
I think the Streetside approach is very sensible and may well be better than Streetview in cities.  However, outside of urban areas you would need to use Streetview as the side of a road becomes far less interesting.  IMHO the best product would offer both these approaches.  

*Avatar: up/down, forwards/backwards, left/right
  Camera orientation: yaw, pitch, roll

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