Data and Information

  1. Introduction and definition of terms
  2. Structured vs. unstructured information
  3. Relational Databases
  4. XML
    1. SVG
    2. X3D
    3. XSLT
    4. XMI
    5. XPL
  5. Object DBMS
  6. Content Management System


This section is included because 3D programs may have to deal with large amounts of information such as big scenegraphs with arrays of, coordinates, normals, textures, colors,etc. So it is important to decide how to structure this information in storage. Some programs will use a file format such as X3D which is an XML file, very large multi-user programs may have to be driven from a database.

Another reason for this section is that we may want to process the program itself, for instance, XSLT might be involved in producing different language versions of the program.

Definition of terms

Structured vs. unstructured information

Information such as free formatted text is said to be be unstructured, that is, there is no particular order or syntax in the data. The opposite extreme is a database which forces the information to be stored in a certain way.

The advantage of structured data, such as databases, is that it allows automation of tasks involving the information.

So it is a good idea to store the information in as structured way as possible, but different types of information permit different types and amount of structure.

Information Content

There is a mathematical measure of information content as defined by Dr Claude E Shannon of Bell Research Laboratories.

How much information a message contains depends on the extent to which it resolves uncertainty

The quantity of information associated with a probability of p1 is I(1/p1) = log(1/p1)

where I denotes quantity of information.

The key problem that Shannon was trying to solve concerned transmitting messages through various channels: telephone, television, radio, and so on. All transmission channels tend to partly change or corrupt the message being transmitted due to random signals that get mixed up with the intentional signals. This corrupting factor is called noise.


Knowledge is power

Proverb 17th c.

The more the data banks record about each one of us, the less we exist.

cover The Medium Is the Massage - Marshall mcLuhan

I only ask for information

Rosa Dartle

cover David Copperfield - Charles Dickens

A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.

Alexander Pope (1688-1744), English satirical poet. An Essay on Criticism.


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