"이것은 저쪽에 있습니다."
Translation:This is over there.
The difference is if the subject of the sentence is the object or the object's location. So -기 always refers to a tangible object but -쪽 is a place or direction. 저기 implies "the object we were discussing is in fact the object right there," and 저쪽 implies "the object we are discussing is located there or that way."
In ENGLISH (and, perhaps, other languages) it is semantically strange to say this construction, though still, technically, grammatically correct.
Remember, friends, other languages treat the concepts you know differently and may even think in different ways, so don't get too hung up on it