What is meta data (meta Date)

While reading the Web information Architecture , the Nineth chapter talks about Thesaurus, controlled thesaurus and metadata. At that time, the definition in the book was very vague, and the length of the lecture was small, and there was no care and no complete understanding. The concept of metadata is mentioned again in chapter Fourth of the "splendid Blueprint" today. So I looked for some more information seriously understand a bit.

What is meta data?

metadata (meta Date), data about data, or information called to describe data or information.
These definitions are very abstract and we can simply understand the metadata as the smallest unit of data . Metadata can describe its elements or attributes (name, size, data type, etc.), or its structure (length, field, data column), or its related data (where, how to contact, owner).

Give a few simple examples:
Students who have used digital cameras should know that there is an EXIF information in each digital photo. It is a metadata used to describe a digital image. According to the EXIF standard , these metadata include: Image Description (picture description, source), Artist (author), make (producer), model (model) 、....、 and so on.
Life we fill out the "Personal Information registration form", including name, gender, ethnicity, political appearance, an inch of photos, education, title and so these are locked Kent.zhu this person's metadata.

In general, metadata can be divided into three categories: intrinsic metadata, administrative metadata, descriptive metadata .
intrinsic metadata; metadata related to the composition of things.
Administrative metadata; metadata related to the way things are handled.
Descriptive metadata; metadata related to the nature of things.
Of course, not that the data can always be clearly divided into the above 3 categories. For example: A Christmas card photo of a puppy with a size of 20K, which was taken by Kent.
Its inherent metadata includes: 20K, JPG; management metadata: Kent shooting, Christmas cards; descriptive metadata: dogs, puppies, Christmas, photos, Christmas 、...
However, the Christmas card can be placed in any one of these categories. Related to the composition of the thing (what it is), related to the way things are handled (what is the purpose of this dongdong), and the nature of things (can be directly used to describe this stuff).

The significance of metadata in information architecture

Metadata is an effective way to ensure that all forms of content on a Web site are actually found. For example, we often worry about a beautiful picture that we saw a long time ago, and if a picture site is good enough for the information architecture, we can rely on the metadata we recall (about Kutoran?). It was taken in 2000? ) to find it clearly.
metadata to information architecture is like the bricks and mortar of a house, it can be placed into different information retrieval system according to the need. Metadata is the foundation of all organizational systems, and navigation systems from search to E-commerce sites are strongly dependent on metadata.
As mentioned earlier, the metadata is actually for the product's lookup (findability) service . The user is not looking for information in accordance with machine thinking to find (will not enter the ID of the photo), but directly input information on the descriptive information such as: "Puppy Christmas card." It also means that when creating descriptive metadata, try to extract the story that the officer tells about the object, which is the detail of what people can remember and search for.

We will find that the mechanical generation of metadata is often unreliable, such as when the Uch system to publish the log when the system will automatically according to the title of the mechanical analysis generated by some of the metadata.
Making full use of manual metadata (handcrafted metadate) is a good way to improve accessibility. The most common example is the tag we see. Tag is a user-created metadata, characterized by no hierarchy, customization. For example, the manual meta data under the Flickr photo provides more convenience for looking up on Flickr.