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Re: Question on gps info in cellphone-snapped pictures -- for short article on mobile web

From: Stephane Boyera <boyera@w3.org>
Date: Thu, 10 Feb 2011 08:09:25 +0100
Message-ID: <4D538F25.6050409@w3.org>
To: CE Whitehead <cewcathar@hotmail.com>
CC: public-mw4d@w3.org
Hello CE,

> I see; so providing that the right phone was used, someone could in
> theory photograph water supplies and runoff (and collect data as well
> though that's irrelevant here), and those photos could be tagged with
> the geolocation, even in Africa? (Correct me if I'm wrong . . .
> otherwise thanks for this info.)

no you are not wrong. this is exactly that, and i'm myself using this 
feature all over the world with my android phone. The beauty of this is 
that it is exif, so the tag is within the photo and is standardized. So 
anyone taking a picture and sending it through e.g. mms will send along 
all the tags, including the geolocation ones.

Best
Stephane

>  >
>  > > 2. Is having a mobile-ready web page normally include the idea of
>  > > having a page that does not take much bandwidth to download? And is the
>  > > likelihood of getting a 404 not found message in the third world
>  > > increased because of bandwidth issues?
>  >
>  > there are two parts in your questions.
>  > i start with the latest one: you would never get a 404 due to bandwidth
>  > issue. a 404 is generated and send by a web server, so that that means
>  > that your request has reach the targeted web server which in does not
>  > have the right page and tell you so. The lack of bandwidth would give
>  > you a 'connection timeout' but not a http error code.
>  > The bandwidth issue is at different level too:
>  > - between the user and the internet: ie the pipe of the operator, the
>  > signal and the handset. the bottleneck can be between the user and the
>  > data service provider (ie the operator). there are at least three major
>  > reasons for such a bottleneck: the type of data service (GPRS vs 3G
>  > etc): in most countries today in e.g. Africa only GPRS is available
>  > outside urban area, which means a couple of KB of bandwidth only.
>  > Then you might have a great 3G signal, but if your phone is only a
>  > GPRS-enabled one you wouldn't see any difference.
>  > Finally, even gprs itself has a theoretical bandwidth and an effective
>  > one, which highly depends on the position of the user vis-a-vis the
>  > tower. the weaker the signal, the lower the bandwidth.
>  > - between the operator and the requested web site: even if the user has
>  > a great connection to his provider, then the bottleneck could also be on
>  > the international bandwidth between the operator and the targeted site.
>
> Thanks very much for this detailed reply; I will quote you. Best wishes.
>
> Sincerely,
>
> --C. E. Whitehead
> cewcathar@hotmail.com <mailto:cewcathar@hotmail.com>
>  >
>  > All in one, it is clear that the bandwidth available to user in
>  > developing countries is almost always low. It is therefore critical to
>  > ensure that coding techniques and content development techniques takes
>  > that constraints into account.
>  > It is also important to note that the bandwidth is not the only reason
>  > for making the page small. As most data service plan (pre or post paid)
>  > are based on time or size of content, making small content means a
>  > cheaper one for the user. There are also device limitation, particularly
>  > memory limitation that would make some bigger content not
>  > usable/accessible/displayable on some devices.
>  >
>  > The Mobile Web best practices (MWBP http://www.w3.org/TR/mobile-bp/ )
>  > has a lot of recommendations concerning small content.
>  > However, most of the MWBP are about why to make small content, and
>  > where, but not really how. This is more hands-on expertise. For instance
>  > W3C has online training courses with specific modules on this topic
>  > (http://www.w3.org/2009/03/mobitrain_course_description.html )
>  > The Web Foundation is running face-to-face training in Africa with also
>  > modules on this topic (see http://www.mobilewebghana.org/training.html )
>  >
>  > Let me know if you have other questions
>  > Stephane
>  >
>  > --
>  > Stephane Boyera stephane@w3.org
>  > W3C +33 (0) 5 61 86 13 08
>  > BP 93 fax: +33 (0) 4 92 38 78 22
>  > F-06902 Sophia Antipolis Cedex,
>  > France
>

-- 
Stephane Boyera		stephane@w3.org
W3C				+33 (0) 5 61 86 13 08
BP 93				fax: +33 (0) 4 92 38 78 22
F-06902 Sophia Antipolis Cedex,		
France
Received on Thursday, 10 February 2011 07:09:32 GMT

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