What is the difference between 어디야? and 어딘데?

Question

Answer

어디야? - where are you?
and 어딘데? - where are you?  where is it?

1) 어딘데 is a Kyungsang-do dialect.  It means 'where are you?' 

2) 어딘데 is short for ''어디인데?''  (If a person who speaks stardard Korean says this)   
    it might sound '어딘데?'

Situation 1. (Where are you?)
 A and B are supposed to meet at 1 pm
A: I will be late about 30 minutes.
B: WHAT? 어디인데? The meeting is very important and about to start in 5 minutes.
A : Sorry. I just passed the xx department store.
* Please focus on the nuance and tone. 

Situation 2 (Where is it?)
A : I found a nice Korean restaurant.
B : 어디인데?
A : The opposite of the xxx station.