Re: thoughts towards a draft AR WG charter

Hello everyone,

First, I'm glad to see this discussion going on, this is great!  My apologies for not sticking to the +/-1 format.  As Christine mentioned I'm the W3C staff person who will be helping out this group.  There's been a lot of great discussion, and I'd like to offer my two cents before we dig into drafting a charter.

Looking at the AR workshop report [1], it states two aims for a new WG, one of which is:

"To develop a standard for representing Point of Interest (POI) data."

This seems like a straightforward statement, but I've noticed that it seems like we don't have a common definition of POI.  Are they represented by a single set of coordinates?  Are they only locations fixed in space relative to Earth?  What is the information that pertains to them?  I'd like to offer a straw-man definition of POI for the purposes of discussion here, lets bat it around and see if maybe some of the issues get resolved along the way.

[[
A Point of Interest is an entity which has a location and about which information is available.
]]

That's hopefully not very controversial, though it does raise more questions:  What is a location?  What information?  So let me take a shot at those definitions too:

[[
A location is a point in space that may be expressed in a geodetic system (e.g. lat/lng in WGS84), or relative to something else (e.g. "near", "in"), or a qualitative expression (e.g. "indoors", "near public transportation", "unknown").
]]

This is more controversial as it includes complex notions of location that are probably beyond what people include in their definition of the term POI, but I think it is more useful in this context.  I don't know that it covers all cases, and I don't know just how much of that is ready for standardization, but it's a starting uh, 'point'.

What information might we want to attach to such locations?  Well, anything, and that should be possible in whatever we do, but there is a set of very useful information that we could likely agree would very useful to standardize: name, shape, and temporal information.

Name seems fairly straightforward and is probably something we can adopt from elsewhere.

Shape information, on the other hand, is more complex.  For starters, not all POIs have a shape (e.g. points such as 'center of this room', 'corner of Mass Ave and Vassar St'), or maybe a point is a shape here?  Some POIs may have a shape that's sufficiently described by a simple 2d circle, bounding box or polygon (e.g. "Empire State Building" may have a rectangle representing it's base at ground level), or 2d with a height (e.g. "the Empire State Building" is a rectangle that is 443 meters tall).  Some POIs might best be represented by a three-dimensional model of varying levels of complexity and detail  (e.g. "the Empire State Building" is a rectangle with a pyramid on top or a complex CAD-like model).  I'm not sure we can standardize each of those cases immediately, but a polygon with a height seems doable, and again could be something that is available elsewhere.

Then there's the notion of time.  All of the information about a POI may change over time: the POI could move, its shape or name could change, it could cease to exist, or be created in the future.  The ability to add temporal information to each of the properties would give us quite a bit of power.  Perhaps this isn't required, but I think it opens a whole set of possibilities that could be difficult otherwise.

Add "Web-style extensibility" (as Dan called it [2]) to these three concepts (location, shape, and name each possibly annotated with time information), and we've got a pretty flexible definition of a POI that could describe traditional POIs such as "Times Square", as well as more complicated ones like a traveling circus, or even less obvious ones like this pen on my desk.

If we could standardize these properties, then we'd have a powerful format that could be used in AR as well as other applications.  If we take advantage of extensibility, we could build a vocabulary for common properties right out of the gate (e.g. description, owner, open/close hours, etc).  Meanwhile, we could also work on covering the more complex possibly AR specific properties such as an image to be used in image recognition property, or other properties that may be used for the non-location-based query use cases.  With these things, we would cover the POI action in the report.  We could of course address other topics, like triggers.  (I haven't addressed that in this message as I'm not 100% sure I understand.  Sometimes they read like complex queries, other times like the POI itself is the trigger.)

What would this mean for where the work goes?  Well, given how useful a POI format is beyond AR, and the amount of work, my straw-man proposal would be to create a POI WG with a primary use case of AR that would develop a POI Recommendation, AR vocabularies, etc.  In the future, as the core POI work winds down then perhaps recharter as an AR specific WG.

So, that's my thoughts, let me know what you think.

Thanks,

-Matt Womer
W3C staff, Ubiquitous Web Activity Lead

[1] http://www.w3.org/2010/06/w3car/report.html#action
[2] http://lists.w3.org/Archives/Public/public-poiwg/2010Jul/0004

Received on Friday, 30 July 2010 17:34:54 UTC