Data Handling

Topic 1

Data

InformationWhen data is given a structure and put into

context it becomes informationa word processed document that we can read

and understandA computer interprets and executes instructions

to process the data into informationEg:

Today + will + be + temperature + hot + a + 32 + day + a + with + degrees + of

Today will be a hot day with a temperature of 32 degrees

Classifying data as information is not always clear and absolute.

What is information to one person may be data to another person.

Information is a vital tool.

Organisations cannot exist without it’s data/information. ‘the more information the better’ – only if the

information is suitable, accurate, timely and reliable

Data Coding

AnalogAnalog data is represented by using continuous

signals [wave form] that vary in strength and quality.

Eg: an analog clockBecause the movement is continuous, a measurement may be taken at any time.

Eg: Human speechPeople combine words into sentences which are continuous

DigitalComputers are digital

They recognize two states: off and on

Digital data is represented using discreet measurements in the form of digits/numbers – 0 & 1

The two digits [0 & 1] represent these two states 0 represents the electronic state of off 1 represents the electronic state of on

Eg: a digital clock Shows the time as a certain number of hours and minutes. Time does not change continuously, but in a series of steps, jumping from second to second and minute to minute.

BinaryA digit is a single place that can hold numerical

values between 0 and 9 - base-10 number system – known as decimal number system.

Computers happen to operate using the base-2 number system, also known as the binary number system.

Why base-2?Because it makes it a lot easier to perform with current electronic technology.

BinaryTechnology uses a binary system that has just two

unique digits – 0 & 1

Each digit is called a bit (Binary digIT)

A bit is the smallest unit of data that a computer can process

On it’s own a bit is not very informative

When 8 bits are grouped together as a unit, they form a byte.

A byte provides enough different combinationsof 0s and 1s to represent 256 individualcharacters.

Units of Measurement

Binary How do you figure out what the value of a binary number

is? You do it in the same way you would for a decimal number, but you use a base of 2 instead of a base of 10.

Decimal [6,357]: (6 * 10^3) + (3 * 10^2) + (5 * 10^1) + (7 * 10^0) = 6000

+ 300 + 50 + 7 = 6357

Binary number [11]: (1 * 2^3) + (0 * 2^2) + (1 * 2^1) + (1 * 2^0) = 8 + 0 + 2

+ 1 = 11

You can see that in binary numbers, each bit holds the value of increasing powers of 2.

Convert binary to decimal

Convert decimal to binary

Data Types

Data Types

NumericTextHypertextAudiovisualPhysical

Numeric

Consists of numbers and decimal points.

Both arithmetic operations (+ - * /) and logical operations (and, or, if, not) are performed on numeric data.

Numbers can be used for calculations as well as sorted and compared to each other.

A common file extension for numeric data include:

.xls (spreadsheet)

TextCan contain any combination of letters, numbers and

special characters.

Sometimes textual data is known as alphanumeric data.

Text is organised into words, sentences and paragraphs.

Some common file extensions for text include:.doc (document)

.txt (text)

.rtf (rich text format)

Essays, reports, letters, emails are examples of textual data.

HypertextText displayed on a computer or other electronic

device with references (hyperlinks) to other text that the reader/user can immediately access, usually by a mouse click

Some file extensions for hypertext include:.html

.htm

AudiovisualVarious forms of data that we can hear or

see

Data takes the form of graphs, drawings, photographs, video sequences and sound.

Audiovisual - graphicsThere are two types of graphics

Bitmapped graphics Each image is a pattern or map of tightly packed

dots (ie bits) Each dot [a pixel – picture element] has a

separate memory position that is represented by a colour or shade of grey

when you enlarge a bitmapped graphic, youenlarge each pixel creating a staircase pattern called aliasing or “pixelated” e.g. photographs

Most images on your computer are composed of bitmaps

Vector graphics Not made up of a grid of pixels Allows continuous lines to be drawn comprised of paths which are

defined by a start and end point Graphics are stored as mathematical formulas These graphics can be scaled to a large size and not lose any image

quality

Audiovisual - graphicsCommon bitmap file extensions are:

.bmp - bitmap

.jpeg- Joint Photographic Experts Group

.gif - Graphics Interchange Format

.tif - Tagged Image File

Common vector file extensions are:.ai – Adobe Illustrator.eps – Encapsulated PostScript file.svg – Scalable Vector Graphics file.drw – Drawing file

Audiovisual - audioAn electrical representation of sound

which can be transmitted or reproduced

Common file extensions include:.mp3.wav.midi

Audiovisual Video and Animation

VideoThe technology of electronically capturing,

recording, processing, storing, transmitting and reconstructing a sequence of still images representing scenes in motion

AnimationThe rapid display of a sequence of images of 2-D

or 3-D artwork or model positions in order to create an illusion of movement.

Common file formats for video include: .mpg, .mov

Common file formats for animation include: .swf, .gif

PhysicalCaptured from the environment.

Light, temperature and pressure

The temperature of a room may be controlled by a computerA thermostat is set to sense the air

temperature. When the temperature exceeds a specified level, a cooling system is turned on. The warmth of the air is used as physical data input into a thermostat to regulate room temperature.