1. Personal Data (Private Use)

• When your Apple Watch records your heartbeat → it’s your personal data.
• Stored on your iPhone or iCloud, only you (and maybe your doctor if you share it) can see it.
• Same with CCTV — if you install it at home, the video is your private data, not Big Data.

2. From Personal Data → Big Data

Data becomes part of Big Data only when:

• It is collected from many people/devices.
• It is combined and analyzed together to find patterns.

Example:

• Apple Health: If millions of Apple Watch users agree to share anonymous health data, Apple can study overall fitness trends (like average heart rate, common sleep problems). That’s Big Data.
• Smart City CCTV: If the government collects video feeds from thousands of cameras across a city, it can analyze traffic flow or crime patterns. That’s Big Data.

3. Why Not All Data Becomes Big Data

• Personal data belongs to the individual.
• Only when it’s aggregated (combined) and anonymized (no personal identity attached) does it become part of Big Data for analysis.

Simple Analogy:

• Personal Data = Your own diary (private).
• Big Data = A library made from thousands of diaries (anonymous + combined → used for research).