What is the difference between analog and digital data?

Digitization means representing data in a way that allows it to be stored, processed, and transmitted by computers.

If we measure temperature using a mercury thermometer, it is an analog representation because the mercury inside the glass tube reacts to the surrounding temperature and gains or loses volume. As a result, the displayed temperature also changes. The mercury can display any possible value within the tube. The temperature is therefore represented analogously.

However, there are also more and more digital thermometers and weather stations in which the temperature is not measured using mercury or another liquid, but instead by a sensor using electrical voltage. The measured voltage is still analog, but we cannot do much with this information directly.

An analog signal describes the progression over time of a continuous value. By sampling at predefined points in time and assigning a value, a digital signal can be created. This process is called sampling. Digital thermometers display the temperature as numbers on a screen. In this case, not every possible temperature can be displayed anymore, but only certain values, for example in increments of 0.5 degrees. We then speak of a digital representation or digital reproduction.

While the analog representation of data is continuous and therefore theoretically infinitely precise, data in digital representation can only be reproduced discontinuously using a limited set of symbols. Therefore, losses occur when converting analog values into digital values. This is where the principle of abstraction applies. Details that are not absolutely necessary for understanding are omitted. If too many details are removed, the original value can no longer be recognized.

Digital images of the real world can be stored, transmitted, or copied without loss of quality and usually at very low cost. These digital codes can be stored on various media such as hard drives, USB sticks, or in the cloud. Digital media are media that work with these digital codes. Computers require digital codes. In nature, however, almost all processes are described in analog form.