Data compression

Data compression is the reduction in size of data without losing any information. A simple example of data compression is a so-called run length coding. It is e.g. used in a fax for the compression of data. A fax transmits the color of the pixel (black or white) and the number of pixels instead of all individual pixels. The same kind of method is also used by GIF for the compression of image files with a limited number of colors.

On the other hand data reduction is used to describe a process of data reduction when information is lost. Such processes are mostly used for sound and images. They save data where the ear or the eye cannot notice or can hardly notice the difference.