Data Representation

Mind Map by , created almost 6 years ago

Cambridge IGCSE Computing Mind Map on Data Representation, created by zeligho9 on 01/09/2014.

Created by zeligho9 almost 6 years ago
2.1.4 Data Representation
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Data Representation
1 Images
1.1 Bitmaps
1.1.1 Image divided into a grid of pixels Each pixel set to a number of bits, which can contain a set number of colours If the pixel contains 4 bits, it can contain up to 2^^4 number of colours (16) Increasing the size of the image increases the size of the file as there are more pixels Increasing the resolution (quality) also increases file size
1.1.2 The width of the picture is needed in pixels as well as the number of bits assigned to each pixel
1.2 Vector Images
1.2.1 These images do not have any data pixels but they are a specific set of instructions needed to reproduce the picture Certain elements of the picture are required to make the instructions Shape Line thickness FIll Colour Depth
1.2.2 Vector images build their instructions in relation to the photo's point of origin As the picture is only a set of instructions, resizing the photo does not affect the resolution of the picture Therefore file size is small
2 Metadata
2.1 Known as "data about data"
2.1.1 vector images need metadata
3 Number systems
3.1 Binary
3.1.1 Base 2 counting system, where only the numbers 0 or 1 are used Computers read data in binary
3.2 Denary
3.2.1 Base 10 counting system where the numbers 0 to 9 are used Humans use denary to count
3.3 Hexadecimal
3.3.1 Base 16 counting system where the numbers 0 to 9 are used, and the letters A, B, C, D, E, F are used to represent the numbers 10, 11, 12 ,13 ,14 15 respectively
4 Units of Information
4.1 Bit
4.1.1 Nybble Byte Kilobyte Megabyte Gigabyte Terabyte Petabyte Exabyte Yottabyte Zettabyte
5 Sound
5.1 Sound waves are analogue, so they must be converted to digital information for computers
5.1.1 This is done by sampling the wave and storing a digital representation of the sound Sampling frequency is how often a sound wave is sampled Increasing sample frequency produces a better quality of sound but increases file size Sample rate determines how many different tones can be represented High sample rate means more tones can be represented

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