[webkit-dev] Multiple location providers in Geolocation API
steveblock at google.com
Mon Feb 2 05:18:26 PST 2009
> 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.
Sure, I agree.
>>>> 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 don't think it has been covered there, but this is an implementation
detail I think.
> 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.
Sure, but the present code does not pass the necessary information to
the platform-specific GeolocationService. So an implementation is not
able to limit the use of high-accuracy providers to times when a
request that specifies enableHighAccuracy is in progress. In order for
the platform-specific implementation to decide on a policy, we need to
pass to the GeolocationService both the 'registration' and
'unregistration' of enableHighAccuracy-enabled requests.
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