I am very beginner to game programming and Libgdx. I am really confused what camera viewport size should I use. In some articles i found that they used 480x800 which is same as target device size. In some articles I found the use meters as 5x5 meter.

So which method is better and how (if you can give some benefits).
If I use meter unites for camera viewport then which is first mapped, width or height.

> 
> If i use 5x5 meter for 480x800 pixels device then visible area of world
> 
> 
> height = 5 meter = 480px and  
> 
> width = 800/480 \* 5 = 8.33 meter  
> 
> **or**  
> 
> width = 5 meter = 800px and  
> 
> height = 480/800 \* 5 = 3 meter
> 
> 
> 

Is it correct calculation of visible world size and which is used first or second.

*I am confused when they start using meter for size everywhere instead of pixels. like actor size is 1x1 meter even it is only 64x64 px. It is really difficult to estimate position and size for me.*

Please link any good article about camera and camera units.