Help:Suggestions

After you have successfully installed Semantic MediaWiki and tested it, what then?

Some draft notes

[edit] Next steps after install

The INSTALL document (view 1.0.1 version) explains how to install Semantic MediaWiki and then test your installation.

From its FAQ section, here's a basic "what to do next".

[edit] I installed Semantic MediaWiki and all went fine. What should I do with it now?

Semantic MediaWiki is there to help you to structure your data, so that you can browse and search it easier. Typically, you should first add semantic markup to articles that cover a topic that is typical for your wiki. A single article, semantic or not, will not improve your search capabilities.

Start with a kind of article that occurs often in your wiki, possibly with some type of articles that is already collected in some category, such as cities, persons, or software projects. For these articles, introduce a few properties, and annotate many of the articles with the property. As with categories, less is often more in semantic annotation: do not use overly specific properties. A property that is not applicable to at least ten articles is hardly useful.

Templates can greatly simplify initial annotation. Create a flashy template for your users to play with, and hide the semantic annotations in the code of the template. See smw:Help:Semantic_templates for more information]]. Use the ParserFunctions extension to implement optional parameters, so that your users can leave fields in the template unspecified without creating faulty annotations. (New, not in FAQ:) If you already have templates that give values and relationships (like the infoboxes on Wikipedia pages), then you can modify these to create semantic annotations. After refreshing all pages that use the template, you will have lots of semantic annotation.

Develop suitable inline queries (the {{#ask: }} parser function) along with any new annotation. If you don't know how to use some annotation for searching, or if you are not interested in searching for the annotated information anyway, then you should probably not take the effort in the first place. Annotate in a goal-directed way! Not all information can be extracted from the annotations in your wiki. E.g. one can currently not search for articles that are *not* in a given category. Think about what you want to ask for before editing half of your wiki with new semantics ...

If in doubt, choose simple annotations and learn to combine them into more complex information. For example, you do not need to have a category for "European cities" -- just combine "located in::Europe" and "Category:City." In any case, if some annotation is not sufficient, you can still add more information. Cleaning too specific and possibly contradictory annotations can be more problematic.

Regularly review users' use of categories, properties, and types using the Special pages for each.

[edit] Naming

[edit] Property names

See old Help:Attribute_name and Help:Relation_name.

A property whose value is a number or unit is pretty unambiguous, so you can just use a noun or noun phrase for it without ambiguity: Population, Area, Maximum speed, etc.

However a property whose value is of Type:Page (another wiki page) is ambiguous if just a noun. If you just use Capital, then if page Foo has the fact Capital Bar , it's unclear whether it "is the capital of Bar" or "has as its capital Bar". So English installations tend to include a verb in such page properties to make the direction of the relationship clearer: Has capital or Is capital of.

[edit] Category names

A big decision is whether to use plural in the sense of a class of things (thus Category:Cities) or singular in the sense of "is a City" (thus Category:City). The former is the English Wikipedia approach, latter is what ontoworld tends to use.

[edit] Enforcing consistent values

You can use the special property Property:Allows value with any property of any datatype to enforce a limited set of consistent values for the property.

[edit] Cooperating with the Semantic Web

• Edit Sites using Semantic MediaWiki and add your site.
• Submit your web site to various ping services such as http://pingthesemanticweb.com/

[edit] Making your data meaningful

Note that if your site is public you can't avoid participating in the semantic web. Spiders will crawl your site and determine link relationships. Increasingly, they will notice the <link rel="alternate" type="application/rdf+xml" ... links to Special:ExportRDF in your pages' HTML and read the RDF representation of your pages.

There is much research and development of meaningful ontologies for representing knowledge. Note that even if your semantic wiki uses well-known terms like "subclass of" or "foaf:knows", they won't be meaningful outside your web except as common words.

If an ontology matches your annotations, you should import it so that you can associate your property names with its vocabulary. The good example is the foaf "Friend of a Friend" spec; you can see ontoworld's use of foaf terms in its Template:Person when you export a person's page on ontoworld as RDF. [1] lists some common vocabularies.

[edit] Strict meaning of MediaWiki categories?

As its help says, SMW's smw:Help:RDF export imposes a particular interpretation of MediaWiki categories. You need to decide whether your own wiki's use of categories is allowed to conflict with that or not. ...

[edit] Properties

The default for a new property is Type:Page. This is a useful default because it allows you to add to those pages explaining their use. For example, if users make the annotation [[Year founded:1997]], you might first think the property should be changed to Type:Date. But in time it could be useful to have a page for each common year founded, and on it do a reverse query to show everything founded on that year.

Users will make annotations that refer to pages that don't exist, that's a useful hint they may have mistyped the name. It may be fine to have lots of properties that don't exist.

[edit] Custom Types and Units

ontoworld has a selection of custom types showing how to define conversion factors for the properties you want to use. For comprehensive conversions, the UNIX units program has an extensive database of conversion factors between units. ...

[edit] Help and documentation

You can refer to the documentation pages on http://semantic-mediawiki.org or copy them to your site subject to the copyright notice.

You should document every property that users create to guide their use. You should specify the type of every property.

If lots of people use your wiki you will find competing names and ideas for annotations.

• Templates like Template:deprecated annotation and Template:deprecated annotations help flag annotation names that need cleanup.
• You can make one a subproperty of the other during cleanup.