W3C home > Mailing lists > Public > public-geolocation@w3.org > March 2009

Re: PositionOptions.timeout & UserAgent permission

From: Greg Bolsinga <bolsinga@apple.com>
Date: Thu, 19 Mar 2009 11:12:09 -0700
Cc: public-geolocation <public-geolocation@w3.org>
Message-Id: <A286DAD0-CF3B-439B-8FAF-B7F19143B66E@apple.com>
To: Andrei Popescu <andreip@google.com>
On Mar 17, 2009, at 4:18 AM, Andrei Popescu wrote:

> An implementation could provide fresher cached results than a single
> application can.
>
> For example, app1 runs at t1 and app2 runs at t2, where t2 > t1. When
> you run app1 at t3, the 'lazy position' was recorded at t2, whereas
> app1 can only remember the position at t1.

This is why I think it should be an implementation detail, instead of  
API.

If there was only the watch method, the first location returns quite  
quickly, and may be the stale location from app1, t1. The accuracy  
would be appropriately set. If this is all the client wants, they will  
get it.

Then as the servers looking up known WiFi addresses come back with  
information, you get a more accurate callback. You use this.

Then as the GPS has warmed up and you get that location, with its  
appropriate accuracy, the client uses this.

In the meantime, the UI for the apps shows more and more accurate  
locations as it goes along.

In addition, the client app runs its own timeout, outside of the  
machinery of Geolocation.

-- Greg
Received on Thursday, 19 March 2009 18:12:51 UTC

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