In Samuel Martin's 1975 A Reference Grammar of Japanese, he calls this use of
に the "copula infinitive" (p.396). But more importantly, he glosses it in English with the word "as":
"As customers we have mostly foreigners, so lots of foreign vegetables like asparagus and broccoli are out for sale."
He also gives an example that closely parallels yours, using
〜の一つに ("as one of 〜"):
"As one of the Hawaiian Islands there is the island of Maui."
= "Among the Hawaiian Islands is the island of Maui."
In this example, "among" is a more natural expression in English, but "as one of" is a little closer to the literal meaning of the Japanese.
As you can see from these examples,
に isn't really marking a location; it's functioning adverbially.