Tag cloud
. A Tag Cloud - engl: tag cloud - (also word cloud, tag matrix or keyword cloud; rarely label cloud) is a method for information visualization, in which a list of keywords, often in alphabetical order, is displayed flat, with individual differently weighted words bigger or in any other manner are highlighted. You may thus two dimensions order ( alphabetical sorting and weighting ) at the same time and make visible at a glance.
Word clouds are being increasingly used in the Community and indexing in weblogs. Known applications are the representation of popular tags on Flickr, Technorati and Del.icio.us.
Tag clouds were probably first used in 2002 by Jim Flanagan and first as a weighted list ( engl. weighted list) called. To some time earlier in 1992 but was already the book " A Thousand Plateaus. Capitalism and Schizophrenia " by Gilles Deleuze and Felix Guattari out on its cover an already " Tag cloud " is shown.
Creation
In principle, the font size of a key word in a tag cloud is determined by its frequency. For a word cloud of categories a weblog the usage frequency for example, corresponds to the number of blog entries that are assigned to a category. At low frequencies it is sufficient to specify directly the font size for any number from one to a maximum value. For larger values , a normalization should be performed. In a linear normalization, the weight of a descriptor is mapped to a size scale of up to, where and specify the range of the existing weights.
- : To display font size
- : Maximum font size
- : Minimum font size
- : Frequency of the relevant key word
- : Frequency at which a tag is to be displayed
- : Frequency of the most common key word
Since the number of indexed objects is per Keyword usually distributed according to a power law, a logarithmic representation is useful for wider ranges of values . For inflected languages such as German, the words must lemmatized before counting first, are thus reduced to their base form.
For the creation of tag clouds are usually used specially suitable software. For example, there is software that automatically elicit from texts or websites, the keywords and their frequency and the tag cloud generate .. Other programs in turn need a list of key words and their weight to generate the tag cloud.
Perception
In some empirical usability testing, the perception and impact of tag-cloud was investigated. It was found that keywords that have the following characteristics learn more consideration:
- Tags with a large font size ( effect influenced by other factors, such as number of letters or adjacent Tags )
- Tags in the middle of the tag cloud ( effect influenced by the particular layout of the tag cloud)
- Tags in the left upper quadrant ( effect influenced by Western reading habits )
Ease of use
In the context of tests in terms of user friendliness has been found that less experienced users often have problems with word cloud: User tests and follow-up surveys have shown that tag clouds do not seem to open up many users intuitive and them unclear why, for example, some terms appear larger than others.
Internet - experienced users, however, can handle word clouds usually easily and see them as often enrich the user experience.
Swell
- Documentation