Tags - Prefix Information

Images contributed to Geograph can have one or more 'Tags' added, these are special labels attached to aid in finding and searching images.

For example, the new image 'Browser' allows easy access to filter and browse images via tags.

Tags are free-form and created by contributors as they need them. Tags can have an optional 'prefix' that refines the meaning of the tag. For example, the tag [airport:London City] has the prefix of 'airport', in this case serving to clarify it's referring to the London City Airport, rather than (for example) the 'City of London'.

We have a number of special meaning prefixes, detailed here:

top:

These are the 'Geographical Context' labels, used to record the very general environment the photo was taken in, and because it's a fixed small list, serves as a very broad categorization system for quick filtering.

Can view the Geographical Context list. Only introduced in March 2011, so many earlier images do not currently have Context assigned.

subject:

This is fixed list of subjects, to convey what the 'primary' subject of the photo is. There are currently about 1000, subjects, but the list will be subject to review from time to time. Contributors should only pick from the provided list, unless there is a good reason to create a new subject.

A Provisional Subject Listing is available, which is designed to help consolidate the list.

Only introduced April 2014, so very few images have an assigned subject.

bucket:

It seems that many are confused by the name "bucket", we are considering renaming to 'pool' as a less arcane term.

A very short and fixed list of technical attributes about the image. Serve to record more about how the photo was taken rather than the subject itself. Done as a separate and defined list, because its hard to define these attributes within the general tags, which typically define the subject of the photo and what is visible.

The list of buckets is available.

NOTE: The list of buckets, was defined before Tags were introduced, and therefore a number of them overlap concept with lists elsewhere. The list is overdue an overhaul to reduce the number of buckets.

wiki:

Little used, but is used to record where the tag duplicates a category assigned to the image on Wikimedia Commons website.

term:

Denotes an automatically generated tag, where a computer algorithm suggested the tag, by extracting words from the image description. (only used as part of a small-scale pilot, not well used)

cluster:

Denotes an automatically generated tag, where a computer algorithm suggested the tag, by looking for related images in the same square. (only used as part of a small-scale pilot, not well used)

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