en. in my opinion, 哪 and 哪里 are not differance... 囧
to abbreviate 哪里 to 哪

for example:
你从哪里来? = 你从哪来?
English: Where are you from?

but when we use 哪, we will say 哪(儿) ,so it will change to 你从哪(儿)来?

i agree his answer!
哪=哪裡

btw
那and哪 is difference
那=there!! ex: right there!在那！
哪=where? ex: where is the bus station?公車站在哪裡？

Exactly, they are no difference.

When used for places:
哪 ＝ 哪里 ＝ 哪儿 ＝ where . They are the same and can be used interchangeably. (Except that 哪里 is a bit more formal )
for example:
你在哪（里/儿）？ Where are you?

Some different usage:
1. 哪里 sometimes can also be used for negation.
for example:
You have a lot of novels! No, i don't.
你有很多小说! 哪里

2. 哪 is often used in inquiry:
你最喜欢哪(一)本书？
Which book do you like most?

天哪！
Good heavens or my god

In these cases 哪 and 哪里 are different and not interchangeable.

hhhhehe, i agree with toto , they have some differance ! when others phraise you, you may modestly say 哪里,哪里 ,it does'nt mean where ,where but only show your modest attitude ,but you can't use 哪，哪to instead, hehe ,that's the differance ,haha : )

In fact, 哪 is more complicated than 哪里. 哪contains the concept of 哪里but expands to many other fields.

Regarding your question,they are similar,but i think they have same usages

哪：
1. pronoun
哪本书是你的？
哪是你家？
2.adv.
be used for a rhetorical question to express negative.
哪+v
我不信，哪有这样的事？

哪里pronoun
哪里有这本书？

"（哪）Which" refers to items that could also be referring to the location, also said that "（怎么）how" and "（哪里）Where" refers to only one location

For example: （哪里）Where is: where are you?
（哪）Which: (1) Where are you? Referring to the location
(2) to the two umbrella "what" a good?这两把伞哪把好？Refers to items 指物品
(3) = how can there be such a thing would be such a thing “哪”有这样的事- that the "how"

請問公車站牌在哪里？Could you tell me where is the bus station?
前面不遠處有一個公車站牌，在那，看到沒？Not too far,over there,you see ?