By future planet classification, I mean how a galaxy-wide civilisation might classify planets. There are many different theories on it, but the idea I like the most is that they will use a combination of different categories. This is an example of such a system.
Line 1: Planet Type: RL: Rocky w/ liquid water, R: Rocky, G: Gas giant, A: Asteroid
Line 2: Gravity: Use plain numbers here.
Line 3: Atmosphere: B: Breathable, E: Exposure Possible, N: None/negligible
Line 4: Hazards: R: Radiation P: Pressure, Tc: Too cold, Th: Too hot, Tch: Extreme seasons, B: Biological.
Line 5: Life: Ai: Advanced intelligent life, Pi: Primitive intelligent life (pre-space travel), L: Non-intelligent life, N: No life.
This system used on different planets in our solar system:
Mercury: R-.38-N-(RTch)-N
Earth: RL-1-B-()-Ai
Europa: RL-.13-N-(RTc)-N
Please note that this is not my idea, I found it on StackExchange and I wanted to share it with this community.