Why is 'Where's it' Grammatically incorrect? [duplicate]
Solution 1:
Because the logical stress in that sentence falls on "is": Where IS it? If you abbreviate the stressed syllable, it results in nothing but nonsense.
Solution 2:
The clitic 's meaning "is" can only be used to substitute for a "weak form" is (pronounced /əz/). The is in in "Where is it" is the "strong form" is (pronounced /ɪz/) since it is used as a main verb and not as a modal (or helping) verb. Therefore it cannot be replaced with the clitic 's.
See a related answer I wrote a while back discussing this restriction in my answer to Is there some rule against ending a sentence with the contraction “it's”?
Solution 3:
Generally speaking, I'm of the mind that technical writing should follow the same conventions as formal and academic writing, which is one reason to avoid the contraction. That being said, I think your intuition is that the sentence itself just "sounds wrong" -- and I would agree. The first part of the sentence refers to "being" (if your column is not country data), but the clause immediately after it refers to location (where is it) -- one clause doesn't follow the other (it is unclear how the type of data in the column is related to where it is).
For example, if the first clause is supposed to convey "If the unit of analysis for the data in this column is not a country", then the second clause should read "what is it [the unit of analysis]", not " where is it".