Geo Metadata in XHTML - Not only one practice

Someone asked me:
> What would be the best way to store geo data in, for example, a blog  
> entry?


Under which forms?
	Latitude? Longitude?
	Name of city, country?
In which markup?
	RSS?
	XHTML?

Oops you said XHTML in the title? Basically what kind of Information do  
you want to put there? It seems there's not only one practice for it.  
Let's try to see photography first.

* Photography

IPTC (Core/XMP) - http://www.iptc.org/pages/index.php

	- City
	- State/Province
	- Country
	(- Location) some software had a location keyword but it's not part of  
the standard. name of a café, of a street, etc.

EXIF (RDF version)

	Exif gives data in Latitude and Longitude with the reference system,  
because there are a few of them.
	http://www.kanzaki.com/test/exif2rdf?u=http://kanzaki.com/works/2003/ 
imagedesc/0721.jpg

    <gpsInfo_IFD_Pointer>
     <IFD>
       <gpsVersionID>2.2.0.0.</gpsVersionID>
       <gpsLatitudeRef>N</gpsLatitudeRef>
       <gpsLatitude>35/43/47.91</gpsLatitude>
       <gpsLongitudeRef>E</gpsLongitudeRef>
       <gpsLongitude>139/42/46.7</gpsLongitude>
       <gpsMapDatum>WGS-84</gpsMapDatum>
       <gpsProcessingMethod>ASCII   GPS-FIX</gpsProcessingMethod>
     </IFD>
    </gpsInfo_IFD_Pointer>



* XHTML : Weblogs, RSS, etc.	
	
in XHTML, we can find this which is usually the location of the person  
who's writing and not the location of the topics. We could easily be  
confused by for traveling webloggers

	- Home Location: address of the weblogger (confusing with weblogs with  
multi-authors, location of the publisher?)
	- Actual Location: If we travel, the place we are at the moment we are  
writing
	- Topic Location: The location of the place we are talking about.

GeoURL/GeoTags have a tendency to encourage to mark-up the place of  
"Home Location".

GeoURL - http://www.geourl.com/
GeoTags - http://geotags.com/
	<META NAME="geo.position" CONTENT="51.5177;-0.1017" />
	<META NAME="geo.placename" CONTENT="London" />
	<META NAME="geo.country" CONTENT="GB" />

Getty - http://www.getty.edu/research/tools/vocabulary/tgn/
	<META NAME="tgn.id" CONTENT="7011781" />
	<META NAME="tgn.name" CONTENT="London" />
	<META NAME="tgn.nation" CONTENT="United Kingdom" />


in RDF, it can be described as
	http://www.w3.org/2003/01/geo/

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#">
   <geo:Point>
     <geo:lat>55.701</geo:lat>
     <geo:long>12.552</geo:long>
   </geo:Point>
</rdf:RDF>



Microformats is still discussing about it

http://microformats.org/wiki/location-formats
http://microformats.org/blog/2005/07/05/locations-microformat

I don't see an easy solution, if there's a guarantee that there is a  
*mandatory* profile in the head of the document to be able to identify  
the reference system. That could be a solution. With the usual problems  
of name clashes, which is not managed by microformats for now.

<head
	profile="@@here URI list of profiles@@">

<span class="geo">
	<span class="lat">37.386013</span>
	<span class="long">-122.082932</span>
</span>



In XHTML 2.0, it will be something ala (I think better for name clashes)

<html
	xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#"… >

[…]
<span class="geo">
	<span role="geo:lat">37.386013</span>
	<span role="geo:long">-122.082932</span>
</span>


What about information encoded under another name? Like for example

	Café Olimpico, Montréal, Québec, Canada

That's very hard to encode that, because addressing system in the world  
are not the same :/ ala IPTC. Be careful markup orgy

	Café Olimpico, Montréal, Québec, Canada

<span class="where">
	<span class="location">Café Olimpico</span>
	<span class="city">Montréal</span>
	<span class="state">Québec</span>
	<span class="country">Canada</span>
</span>

but for a machine that would not be necessary very helpful either to  
make really a usable information. *sigh* and imagine without the  
accents, which will be legal.

<span class="where">
	<span class="location">Cafe Olimpico</span>
	<span class="city">Montreal</span>
	<span class="state">Quebec</span>
	<span class="country">Canada</span>
</span>

We could add a link to Google Maps, but…

<span class="where">
	<span class="location"><a  
href="http://maps.google.com/maps?ll=45.524067,-73.600373&amp; 
spn=0.004749,0.007145&amp;hl=en" rel="geo">Cafe Olimpico</a></span>
	<span class="city">Montreal</span>
	<span class="state">Quebec</span>
	<span class="country">Canada</span>
</span>

Why it should be Google Maps more MapQuest or Yahoo Maps! or anything  
else? The day Google Maps disappears, what's happening with the legacy  
data?

Maybe another solution could be: But I wonder if it's not an abuse of  
title, in fact I think it's an abuse. I would say the other way around  
would be better for title. Welcome to the world of parsing errors or  
spelling mistakes, and how do we know the coordinate system.

<span class="where">
	<span class="location"
		  title="lat:45.524067,long:-73.600373">
		  Cafe Olimpico</span>
	<span class="city">Montreal</span>
	<span class="state">Quebec</span>
	<span class="country">Canada</span>
</span>

The latitude, longitude system is the only agnostic system granting  
that the coordinate system reference is given before hand. No political  
changes (Invasion of a country for example), no name changes (Seine  
Inférieure -> Seine Maritime in France), etc.

I wish there was a service for it, a kind of international *public*  
service.

http://geo.example.org/lat=45.524067/long=-73.600373
	It could return either maps, names of places, etc.
http://geo.example.org/location=café des arts
	It would return a list of possible choices with coordinates.


UN seemed to have conference on topics of names.

[[[
As fundamental to the need for global standardization of geographical  
names, UNGEGN promotes the recording of locally-used names reflecting  
the languages and traditions of a country. UNGEGN's goal is for every  
country to decide on its own nationally standardized names through the  
creation of national names authorities or recognized administrative  
processes. With the wide dissemination of the nationally standardized  
forms through gazetteers, atlases, web-based data bases, toponymic  
guidelines, etc., UNGEGN can promote the use of these names  
internationally. For each non-Roman alphabet or script this will be  
through the adoption and use of a single scientifically-based  
romanization system.
]]] - http://unstats.un.org/unsd/geoinfo/about_us.htm



-- 
Karl Dubost - http://www.w3.org/People/karl/
W3C Conformance Manager
*** Be Strict To Be Cool ***

Received on Friday, 29 July 2005 13:55:02 UTC