From what I understood any difference between that and where (and maybe other "relative particles") is "lost" when translating a subordinate through -dIk. An example from this Lesson: "the village where my father was born" becomes "babamın doğduğu köy" with no explicit indication of the "where".
Of course there is only one way to translate it back to English, but if we substitute doğduğu with yerdiği (and make some strong assumptions about my father's diet), we should be able to translate it both as "the village where my father ate" and "the village that my father ate". Am I correct so far?
So what's different here? Why do we need to explicitly write nerede in this sentence and not just write "Ben olduğumu biliyorum" for both "I know where I am" and "I know that I am" (if we want to get philosophical)?