Chapter 16. Term clouds

A "cloud" is a visual cluster of words or phrases based on some kind of vocabulary. This vocabulary may be the contents of one or more local metadata fields, or a user-submitted vocabulary ("folksonomy"). In dmBridge, there are two types of clouds: those based on social tags (tag clouds), and those based on field vocabulary (vocabulary clouds). These are considered to be distinct subsets of term clouds. Normally, terms in a cloud have some kind of visual distinction from each other (color and/or size) based on the frequency that they appear in the information corpus. On a web page, these distinctions are controlled by CSS properties like color, font-size, font-weight, etc.

dmBridge is able to generate term clouds based on Dublin Core field vocabulary (see DMGenericTemplateHelper::getHtmlVocabularyAsCloud()). Social tag clouds are output by DMGenericTemplateHelper::getHtmlTagsAsCloud(). Both classes output tags as HTML anchor (<a>) elements with no enclosing element. These elements receive a CSS class attribute of dmTagX, where X is an integer from 1 to 10. With social tags, all tags are output with the same class of dmTag.