CategoriesW are a software feature of MediaWiki (the wiki software that powers Appropedia), which enables editors to add pages to automatic listings called category pages.W These help structure a project such as Appropedia by grouping together pages on similar subjects.

A category page lists the articles (or other pages) that editors have added to a particular category. There may also be a section listing the subcategories of that category. The subcategorization feature makes it possible to organize categories into tree-like structures to aid navigation.

Every page on Appropedia belongs in at least one category. It's common for an article to fit into two or more categories. To see the categories in Appropedia:

Adding a category to a page[edit | edit source]

To add a page to a category, type at the bottom of the page.

Categories on Appropedia are used to organize content. For instance if there are many individual articles on the topic of water, it might make sense to create a category for water.

To Create a category called Water type into the address bar

To make a link to the Water category (a visible link, rather than adding the page to that category) type Category:Water . If you want the link to display with different text, type LINKTEXT where LINKTEXT is the text that will be displayed as the link.

To see a category tree see Appropedia:CategoryTree. It is helpful to have the category tree open in another tab when editing a page and deciding the most appropriate categories.

Using categories[edit | edit source]

If you create a new category, it's best to put it within another category. On the occasions when it doesn't fit in another category, then it is a fundamental category, and should contain the tag as the last line of your new wiki category.

If you are unsure, you can discuss it at the Village Pump.

To start a new subcategory, edit the page Category:Your subcategory name and then at the bottom of your wiki enter the line .

How the categories are related[edit | edit source]

A glance at the navigation bar shows several collections:

  • Projects
  • Topics
  • Programs
  • How tos
  • Theses
  • Users
  • Organizations
  • Coordination

And there are more that don't show up in the navigation bar.

All of the collections above are categories, except "Users" (which is a special group due to Appropedia's wiki software). The diagram below is a useful visual aid for discussing how categorization works, but don't take it too literally; attempting to capture the categorization in 2 dimensions is tricky. Refer to it as you read the words below it. Remember that the basic point of categorization is to help users find related content, and this page is meant to describe Appropedia's approach.

Categorization diagram2.JPG

(the diagram above is a first pass...I already noticed that "projects" is missing...and probably includes everything!) (sections below will describe in more detail what the categories are, how they overlap, etc.)

Detailed descriptions of categories[edit | edit source]


Project pages document actual completed or ongoing implementations of Appropriate Technology, which are categorized under Topics. (Projects that are in the planning stages can be described under Category:Coordination.) They may cover multiple technologies, will typically involve an organization and a location. Depending on the level of detail and the style, a project document may also be a How to page. Note: there is an unfortunate confusing usage of the word "project" that comes with the wiki software; in some contexts "project" refers to the content page associated with a "talk" page, even if that page is not an Appropedia Project category page.


Topic categories help to organize technologies. Some technologies fall into multiple technology topic categories. For example, windmill water pumps may be categorized as being under Category:Water as well as Category:Wind power. Project pages should be categorized under one or more Topic categories, as should most How to and Thesis pages. Organizations which focus on a particular technology area can fall into a topic category. For example, International Rivers Network is in Category:Water


Program pages are intended to describe various organized implementation or educational efforts involving Appropriate Technology or Sustainable Development.

How tos

As you would expect, are pages that offer detailed information allowing a reader to implement a particular technology, and would also be categorized under appropriate Topic categories. As mentioned above, Project pages can sometimes be How tos. However, How tos need not be technology focused; How tos can document processes, such as grant application, field assessments, inter-organization engagement, etc. Example: Weld wood


Thesis pages are academic papers related to Appropriate Technology or Sustainable Development. Typically these pages are posted by the authors, and in any case must be posted with permission under the Appropedia:Copyrights. Usually these pages will also be categorized under one or more topic categories.


Users are technically not a category, but a built-in grouping of the wiki software. Users may categorize themselves as being part of an organization, or focused in a particular technology topic.


Organizations are straightforward. Academic institutions, volunteer groups, charitable organizations, NGOs generally, and even governmental groups can be categorized as organizations.


Coordination pages are for managing the actions of several people. These pages can be used to coordinate production of a flyer, or a large project. Example:


Projects and organizations that are located in specific countries (that is, not international) should be placed in a country category. Currently, most of the location categories are countries. As the number of pages grow, it will make sense to add larger and smaller regional groupings, such as continents and subregions of countries, as well as even city categories.

When should a new category be created?[edit | edit source]

Topic categories[edit | edit source]

If a subtopic has very few articles (say, less than about 5), then it may be better to just use a broader category for the time being.

When there is adequate content and/or more articles, the content can be moved to the more specific category. See Help:Moving a page#Moving a category.

Organizations[edit | edit source]

Any organization with its own pages - such as original content and/or its own projects - should have its own category.

Programs and projects with a number of pages can have their own category. If there are is a very small number of pages, it's acceptable to use their organization's category.

Naming categories[edit | edit source]

Use names that make sense to a global audience[edit | edit source]

For example, avoid use season names in categories. A category name such as "Spring 2006", describing the March-May period, only makes intuitive sense for those north of the tropics, not for those in the tropics or the southern hemisphere. However, if it's part of a program name for a specific school or specific location, e.g. "Springfield Summer School," this may be a suitable category name. The category text, however, should specify the period covered in terms of the calendar (dates or months).

Linking to categories[edit | edit source]

There are a few options for linking to categories.

Template[edit | edit source]

{{Cl}}W ("Category list") displays the format used in adding a category to a page (but the template itself doesn't add the category):


displays as:


This is useful when you want to tell someone else about a category, and how to add it to a page, for example when writing help pages, or advising someone on their user talk page.

Category tag turned into a regular wikilink[edit | edit source]


displays as:


Piped category link (changing display text)[edit | edit source]

[[:Category:Mexico|pages about Mexico]]

displays as:

pages about Mexico

Moving category pages[edit | edit source]

See Appropedia:Moving category pages.

CategoryTree[edit | edit source]

The Extension:CategoryTree extension provides a dynamic view of categories in the form of a tree.

The same graphic object can be made to appear by the user on any page, inserting it in the wikicode as a custom HTML tag (or a parser function ), to show the structure of any category.

Category trees can be used in three ways:

  1. directly on the category pages (through the wiki site's settings).
  2. as a "custom tag" to show a category structure in-line on a wiki page.
  3. and as a special page.

The CategoryTree extension adds [+] "expand" widgets to the subcategories listed on category pages. If Javascript is disabled, those widgets just do nothing.

<categorytree> tag[edit | edit source]

The name of the category must be inserted inside the tag, without prefix. For example:

<categorytree>Energy</categorytree> produces:

The tag accepts the following attributes with HTML-like syntax:

  • mode - can be "categories", "pages" or "all". The default for this attribute is set to "categories". (E.g. <categorytree mode=pages>Gardening</categorytree> will show all the subcategories and pages in the Gardening category.
  • depth - determines how many levels of the tree are shown initially. Default is 1, 0 means only the root node. The maximum value depends on the mode specified, and on the $wgCategoryTreeMaxDepth option. note: depth values greater than 1 do not (yet) work with $wgCategoryTreeDynamicTag enabled!
  • onlyroot - set this to "on" to only show the "root" node of the tree initially. Equivalent to depth="0". Deprecated USE depth="0"
  • hideroot - set this to "on" to hide the "root" node of the tree, i.e. the mention of category Foo from the example.
  • style - can be used to specify any CSS styles you would like for the tree.

Parser function[edit | edit source]

You can also use parser function syntax to insert a category tree into a page. It works exactly like the <categorytree> tag, but using a different syntax, the parameters must be set using the typical syntax of templates. For example: {{#categorytree:CATEGORYNAME|mode=pages}}

Example[edit | edit source]




See also[edit | edit source]

Interwiki links[edit | edit source]

Discussion[View | Edit]

Suggested category changes - please comment[edit source]

Note: to display category links, use a colon before the word category, e.g. [[:Category:Energy]].
I like Category:Construction, but whatever we go with we should probably keep Alternative building as a page instead of just a redirect. This page could list some definitions of Alternative building and then prominently link to the main Category. The reason is that potential visitors should be able to Google Alternative building and find us. Another possible solution would be to figure out how to add Meta tag description to pages (so we could put alternative building in as part of the description of Category:Construction or Category:building), and hope the search engines find it. --Lonny 09:30, 16 April 2007 (PDT)

Category guideline[edit source]

See also the discussion on this topic at User talk:Lonny#Photovoltaics how-to?

I think we should readdress our category policy/norms. Any thoughts on the following policy?

Categories include a brief text introduction to the category, including a link boxes to more information from wikipedia or other partners.
In the text is an automatic [[{{PAGENAME}} basics]] that links to a much more detailed page.
In the text is an section for links to more detailed pages such as [[{{PAGENAME}} calculations]]
Subcategories and articles are prominently displayed and mentioned.
It may be time to explore Semantic Mediawiki so that we could automatically generate sections such as =={{PAGENAME}} Organizations==

These are just some starting ideas... and maybe portals are a better place to focus our energy, in which case some of this applies to our portal policies. --Lonny 16:05, 22 April 2007 (PDT)

I like this suggestion. I've always been a bit troubled with having extensive content on a category page, even if I couldn't articulate my concerns. I didn't follow the Semantic link above yet, but will do so in a moment. This discussion of category code changes and mediawiki seems like a good time to mention (possibly remention?) the ability that is now present in Wikipedia category pages, where subcategories may be expanded by clicking on a plus sign. Very cool for viewing the category tree. --CurtB 16:12, 22 April 2007 (PDT)
I like the change in approach, and would like to finalize and implement this soon.
Re the Semantic Mediawiki - that sounds fantastic. I'm not sure of the details of what you're trying to do, but we definitely should explore this. --Chriswaterguy · talk 18:54, 6 May 2007 (PDT)
See an initial attempt at this approach, using {{cat}} (which probably needs a rename) at Corruption. --Chriswaterguy · talk 18:06, 8 May 2007 (PDT) Note I've now created {{topic header}}, & {{cat header}} for category pages - I think these are more promising. I've delete the more basic {{cat}}, which never ended up being used, so that name can be used for something else. --Chriswaterguy 02:48, 15 December 2009 (UTC)

How much should be in a category's edit box?[edit source]

(Some of this - which I wrote for another talk page before finding this one - is touched on above.)

There is a temptation to write a lot about a category on the category page itself.

Disadvantage for users is that it can make for a fiendishly long scroll to find the subcategories and pages that the category system is primarily designed to show. The first category I looked at had what seemed like scores of images down its right-hand side above the subcategories.

My suggestion (probably not original)[edit source]

I believe that, where practicable, the edited part of a category should show very little apart from:

  • Brief summary of subject-matter (possibly clarifying scope of category where the name doesn't define enough)
  • Link to the main article(s) expanding the topic
  • Links to closely related sister-categories or others related somehow (whether internal or in sites such as Wikipedia and Wikimedia Commons)
  • Parent categories if any

The main article(s) about the subject should, naturally, be included in the category (probably with piped links so that they list near the top of the category).

Templates to save typing[edit source]

Wikipedia has standard simple templates you can add right at the top of the edit box giving an even more prominent link to the main article(s). Example: Wikipedia:Category:Education in New Zealand starts with {{catmore1|[[Education in New Zealand]]}}, which produces a neat paragraph thus:

For more information, see the article about Education in New Zealand.

I think there is a template that even seems to cleverly substitute a singular article name where the category name is plural - but I've not checked that out in detail yet. Some of the templates are still under development and may change for the better at any time.

Your template:cat is the same sort of thing but not as clever (and used much less, I presume from its documentation). Similar tricks have been mentioned earlier on this page too. They are probably a valuable part of any final "standard category page contents" policy.

See a heap of such templates at

Robin Patterson 08:52, 27 May 2007 (PDT)

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