[jdev] XEP-0080: adding location source information

[Christopher Orr]

On 10/02/2010 22:49, Tobias Markmann wrote:
> On Wed, Feb 10, 2010 at 22:44, Ilya Braude<ilya at drakontas.com>  wrote:
>
>> I would like to propose the extension of the user location spec with source
>> information, i.e. where the location information is coming from.  Having
>> discussed this topic with several people at the recent summit I think there
>> is enough interest to make it part of the XEP.
>>
>> There are several use cases to motivate this change:
>>
>> Users may get location information from GPS, set it manually, use WiFi or
>> cell tower triangulation, etc. Knowing source information would enable
>> clients to display appropriate icons for the users who publish location.
>>
>> This could also be useful when updating or aggregating information from
>> separate sources. For example, a client that is integrated with a car's
>> systems can send location updates using GPS, and more accurate speed updates
>> from the car's speedometer (thanks to tkoski for the use case).

What kind of granularity is useful -- would you want a <source> for the 
lat/lon (GPS), plus somehow another <source> for the <speed> (speedometer)?

Similarly for <alt> and <bearing>.


>> Devices with built-in digital compasses to send more accurate heading
>> information with a different source tag (this is probably more useful if the
>> device is mounted in a known orientation, such as in a vehicle, but still
>> useful).
>>
>>
>> I think the way to accomplish this is to add a 'source' element as a child
>> of the 'geoloc' element:
>>
>> <geoloc xmlns='http://jabber.org/protocol/geoloc' xml:lang='en'>
>>   <source>GPS</source>
>>   <lat>45.44</lat>
>>   <lon>12.33</lon>
>> </geoloc>
>>
>>
>> An alternative would be to add a 'source' attribute to the 'geoloc'
>> element, but I don't like that as much:
>>
>> <geoloc xmlns='http://jabber.org/protocol/geoloc' xml:lang='en'
>> source='GPS'>
>> ...
>> </geoloc>
>>
>>
>> Another issue to consider is whether to recommend well-known values for the
>> field.  GPS and manual are probably going to be the most common use cases,
>> so standardized strings to represent them would be useful for
>> interoperability.
>
> That sounds sensible. On that topic it would be nice to have a tag for where
> mobile clients could just dump the CellIDs they see and send the stanza to
> the server which would then do the heavy lifting and look the position up
> locally or at a 3rd party service and would replace the CellID tag with the
> coordinates and accuracy tags.

A bit like this? :)
http://xmpp.org/extensions/xep-0255.html#example-5 (or example 7 if 
you're not expecting a reply).

Chris