Wikipedia:WikiProject Bridges and Tunnels/Categorization

This is the categorization page of WikiProject Bridges and Tunnels.

Goals
This project page establishes a guideline to categorize bridge articles in a simple logical manner so that anyone is able to effectively browse the subject here on Wikipedia. This means that clear categorization guidelines must be established. With these guidelines in place, this project can then categorize all the articles in a consistent manner.

This process will also help avoid overcategorization.

Overview
This categorization guideline outlines two schemes. One is for articles where the subject is bridge-related (like bridge, or suspension bridge). The second is for articles about specific bridge(s) (like Golden Gate Bridge or Millau Viaduct).

Currently Category:Bridge is tagged for Category redirect and is empty. Category:Bridges is the root category for all articles of this subject. The category scheme outlined below originates in this root category.

As a subject, bridges are related to the subjects of transport and structures. As such, Category:Bridges is a subcategory of Category:Transport infrastructure and Category:Buildings and structures by type. The articles on specific bridges need to intersect with these categories as well. This is done at the "location" level. By placing an article about a specific bridge into a location category such as Category:Bridges in Japan, it should automatically intersect with these two categories because Category:Bridges in Japan will be a subcategory of Category:Transport in Japan and Category:Buildings and structures in Japan.

In general terms, bridge-related articles need to be placed into Category:Bridges, and may also be placed in a sub-category. For example, suspension bridge is categorized under both Category:Bridges and Category:Suspension bridges (since it is the eponymous category a space would be used as the sort key).

Articles about a specific bridge (such as the Brooklyn Bridge) need to be categorized a minimum of four ways:
 * By structural type (in subcategories to Category:Bridges by structural type)
 * By year completed (in subcategories to Category:Bridges by year of completion)
 * By location (in subcategories to Category:Bridges by country)
 * By mode of traffic (in sub categories to Category:Bridges by mode of traffic)

For more specific quidelines on choosing the correct subcategory in each of these four areas, please see the table below.

Bridge articles should also be categorized according to other WikiProjects guidelines. For instance, under WikiProject U.S. Roads a bridge that carries U.S. Route 66 could be placed in the category Category:U.S. Route 66. It likely will may fall under a WikiProject for one or more a geographic areas. Consider placing any new bridge article into these categories as well.

Another type of bridge articles is one about groups of bridges (such as Bridges in Kiev). These would generally be categorized only by location as they would fit into multiple categories under the other ways.

Marking uncategorized articles
If a bridge article has few or no categories add then add  at the top of the article page to alert other editors.

Most specific categories
In general, articles and categories should be placed in the most specific applicable categories, and should not be placed directly in a "parent" category if they are already present in one of its sub-categories. In other words, if an article is placed in Category:Camcorder films, there is no need to place it in Category:Films shot digitally as well.

Note, however, that this applies only to direct placement into a "parent" category; it is normal for a category to have multiple indirect paths up to some other category higher in the tree. For example, Category:American documentary films is both a sub-category of Category:American films and a sub-category of Category:Documentary films; thus, there are two distinct paths from Category:American documentary films up to Category:Films. This is especially common when dealing with intersection categories.

Categorizing entire sub-categories
One important aspect of the "most specific" principle is that if every article in a category belongs to another category, it is sufficient to nest the categories directly, rather than double-categorizing each individual article. For example, A Nightmare on Elm Street does not need to be added to Category:Film series directly because Category:A Nightmare on Elm Street (franchise) films is already a sub-category of it.

Intersection categories
In many cases, articles can be categorized through several parallel classification schemes, associating them with the related countries, languages, years, and other topics. There are two general ways of applying multiple categories from these classification schemes to a particular article. The simplest, which can be sufficient for unusual combinations or small categories, is to apply each category separately. As with the aforementioned example, an American documentary film could be placed in both Category:American films and Category:Documentary films. However, this system is unwieldy as category sizes increase; thus, common combinations of multiple categories can be made explicit by creating an "intersection" sub-category for them; in this case, Category:American documentary films.

The intersection category can potentially combine an arbitrary number of elements from the overall category structure, but categories that combine two or three are more common. It is recommended, however, to follow existing combinations. For example, Year-Country films categories should not be created, unless the project decides it is wise to do so. This is not so imperative when creating an isolated category somewhere down the line, but it certainly is when this action could open the way for a big number of resulting intersections.

Note that the simpler system can still be used in conjunction with intersection categories to avoid the proliferation of extremely small and narrow sub-categories. For example, it may be better to place an article in both Category:Armenian films and Category:Documentary films than to create an additional Category:Armenian documentary films. A similar approach should be taken if there is no reasonable way to name a potential intersection category.

Practical instructions
In order to keep a consistent order in how we categorize a film article, please follow the following order. In this way one can easily check if all basic categories have been given:

(After last section and after all footer templates, line series, director filmographies, etc.)

(- One empty line here -)

This is needed if the title starts with an article only.

Followed by several usually given sub-categories

(-- Two empty lines here --)

(- One empty line here -)

Interwiki links