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Brainstormin sur le Microformat de Mesure

Cette page rassemble des idées sur la manière d'utiliser le XHTML sémantique pour représenter sans ambiguité les mesures.

Guillaume Lebleu

Exemple basique avec unité élémentaire utilisant le modèle abbr et le code UNECE (voir measure-formats)

<span class="length">5 <abbr class="unit" title="FOT">Feet</abbr></span>

Une "value" optionnelle pourrait être utile dans certains cas, par exemple quand la valeur est fournie en texte clair :

<span class="length"><abbr class="value" title="5">Five</abbr> <abbr class="unit" title="FOT">Feet</abbr></span>

Andy Mabbett

Cette extension Firefox peut se montrer intéressante. Remarquez cependant qu'elle a été critiqué pour avoir un écran "embêtant" : Converter AndyMabbett 15:32, 3 Oct 2006 (PDT)

Je suis l'auteur de cette extension. Je ne veux pas aller plus loin là-dessus, mais je veux simplement clarifier ça brièvement. La section avec le "nag screen" est fausse sur deux points : (1) ce dialogue n'est plus là, et (2) même s'il était encore là, vous n'aviez seulement besoin de lire un paragraphe et de cliquer sur un bouton pour le faire disparaître à jamais -- mais vous n'avez pas à me prendre au mot, installez le vous même et observez. Le compte-rendu d'Andy est pertinenent néanmoins -- l'extension a été critiquée pour ce dialogue (c'est ce que vous obtenez de votre utilisateurs libres d'extensions quand vous leur demandez 15 secondes de leur temps pour des centaines d'heures de votre temps). --BogdanStancescu 09:35, 9 Oct 2006 (PDT)

Bogdan Stăncescu

Here are my findings related to automatic parsing of measurements on web pages while developing the Converter extension. Please ask away if you want me to go into more detail on any of the topics -- I'm not sure which of my experiences are relevant to microformats, so I'm going to give you an overview of my conclusions.

By the way of an introduction, the Converter is a Firefox extension which tries to convert all measurements it finds in any web page to their Imperial or metric counterpart (e.g. Fahrenheit to Celsius, and Celsius to Fahrenheit; meters to feet and feet to meters). There are two steps to the conversion process: (1) identifying the measurements in the page, and (2) converting them. As expected, the conversion part is trivial, at least conceptually. The parsing is the tricky bit, and that's also where the Converter's challenges also become relevant for microformats.

Here are the main challenges I have encountered while writing the Converter:

Presentation standardization
The first, biggest and most obvious challenge is lack of almost any de facto standardization in respect to data presentation. What I mean is that although the units themselves are more or less standardized (more on that later), they are presented in various ways within web pages. Take these examples: "50 foot monster", "50 ft monster", "50 feet monster", "50-foot monster", "50-feet monster" -- and my personal favorite, "fifty-foot monster" (more on this later);
Note that using a microformat using in particular the Abbr design pattern would make each of these examples less ambiguous if not unambiguous. See below --Guillaume_Lebleu:
<span class="height"><span class="value">50</span><abbr class="unit" title="FOT">foot</abbr></span> monster
<span class="height"><span class="value">50</span><abbr class="unit" title="FOT">ft</abbr></span> monster
<span class="height"><span class="value">50</span>-<abbr class="unit" title="FOT">foot</abbr></span> monster
<span class="height"><span class="value">50</span><abbr class="unit" title="FOT">feet</abbr></span> monster
<span class="height"><abbr class="value" title="50">fifty</abbr><abbr class="unit" title="FOT">foot</abbr></span> monster
Of course; as far as I could gather, that's actually the purpose of microformats -- bridging the gap between what humans and machines can understand, no? --BogdanStancescu 00:30, 11 Oct 2006 (PDT)
Unit standardization
I live in Europe, where I've always used the metric system. As such, this probably was a much bigger nasty surprise for me than it is for a user of the Imperial/U.S. Customary system: in the Imperial system, the units themselves vary depending on where you are -- miles, pints, and a whole lot of other units come in many different flavors, but they're all written the same in regular usage;
"1 meter" vs. "1 metre" is a reasonable difference -- but non-SI units are usually translated. Even some SI units have different plurals, depending on the language, although in theory SI units are actually denoted by symbols, not "words", as to make them non-translatable, and truly international (hence the name of the SI). I haven't really given much thought to a solution towards parsing these, because I find it overwhelming for the time.
The sheer number of units
surprisingly, most people don't realize just how many units we humans have invented. Just take a look here: -- see how many categories there are? Now click on Flow Rate -- a non-ubiquitous type of measurement. Three sub-categories only for flow rates! Now click on Volume Flow Rate and take a look at the number of units in those lists. Remember, those are just in one of the three categories for flow rate! The UNECE standard mentioned in the measure formats page is useful to define just that -- a standard set of units. But in practice there are a lot more being used out there.
Do you have examples from the Web (a URL) of non-UNECE units. One possibility would be to provide the ability for a unit to be defined as a division of products of other units. This is consistent with the measure-formats-fr#Systeme_International, which defines 7 base units and all other units as derived units (of course some units, even though they are derived are much easily represented as simple ones). This is what XBRL has done for financial/accounting/reporting. See currency-formats-fr#XBRL and theorical example (ampere acre per second) below --Guillaume_Lebleu:
Unfortunately I don't have URLs -- almost at all -- with measurements, although I've been in the "business" for a while. The reason for this is that I collect URLs of pages I encounter which are not properly parsed by the Converter, and when I release a version which understands those, I delete the URLs. Also, I never intended to cover all units in the Converter myself, for a multitude of reasons -- therefore I was never interested in the more exotic ones.

Guillaume Lebleu's example

<span class="unit">
<abbr class="unit" title="AMP">Ampere</abbr> <abbr class="unit" title="ACR">acre</abbr> <span class="divide">per</span> <abbr class="unit" title="SEC">second</abbr>
Regarding your idea of breaking down the units in base units, that's something I've also been toying with in my head for the Converter. For my particular application, it's technically more difficult to implement this breakdown. For microformats, it would be easier, but there still remains at least one potential problem: you end up with a huge mess in the page. If a standard is too complicated to follow, one tends to give up altogether.
Consider a document which actually discusses some sort of current variation per farm, and therefore needs to repeatedly refer to ampere acres per second. For human use, they'd simply define the AAS somewhere at the top of the document, and then refer to AAS, KAAS or MAAS as needed. Maybe a similar approach should be considered for microformats as well:
We define the 
<span class="unit_definition">
  <abbr class="unit_name">AAS</span>
  <abbr class="unit" title="AMP">Ampere</abbr>
  <abbr class="unit" title="ACR">acre</abbr>
  <span class="divide">per</span>
  <abbr class="unit" title="SEC">second</abbr>
And then use the "AAS" throughout the document as any other pre-defined unit. How would you define (and use) the KAAS (1000 AAS) or MAAS (1,000,000 AAS) though? Is there any standard way already to use data multipliers in microformats? Or should we discuss that? Or is it out of scope? --BogdanStancescu 00:30, 11 Oct 2006 (PDT)

That's all I can think of as major hurdles right now. If I remember anything else, I'll post here. Please do give me feedback here if you want to ask more about any of the topics I touched above, or if you have other questions I might be able to reply to. --BogdanStancescu 12:08, 9 Oct 2006 (PDT)