[webkit-dev] Multiple location providers in Geolocation API

Greg Bolsinga bolsinga at apple.com
Tue Jan 27 10:50:41 PST 2009

On Jan 27, 2009, at 10:44 AM, Steve Block wrote:

> I'm not sure that this is true, as many devices will have GPS - high
> end phones as well as laptops.

Well that platform should manage between GPS and any other providers  
itself? So if this was implemented on iPhone, for example, the  
platform uses iPhone's CoreLocation, and it manages where it is  
getting the data from itself. That is a platform detail as I read it.

>>> On a related note, each time a new request is made, the  
>>> PostionOptions
>>> for that request are passed to the GeolocationService by calling
>>> startUpdating(PositionOptions*). This allows the  
>>> GeolocationService to
>>> estimate which location sources are needed (ie whether GPS is to be
>>> used) for all currently executing requests. However, this will  
>>> always
>>> be an upper bound, as there's no way to remove sources from the  
>>> list.
>>> Again, is this intentional?
> Even if we choose to share the results of all providers between all
> currently active requests, I think we should still limit the use of
> 'enableHighAccuracy' providers to times when a request specifying this
> option is in progress. In the current implementation, once a request
> has been made with enablehighAccuracy=true, all subsequent requests
> will use the 'expensive' providers, until all current requests have
> completed. What do you think?

I think that is a question for the GeoLocation list, in fact I think  
it may have been covered there?

I think that should be left up to the platform, personally. In a  
theoretical iPhone platform, CoreLocation will be as accurate as the  
most accurate request, maxing out with the accuracy the device is  
capable of.

-- Greg

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