haʊˈɛvɚ, ɪn dʒˈɛnɚɹəl bˈoʊθ ðə læɡɹˈæŋɡiən ænd juːlˈɪɹiən spˌɛsɪfɪkˈeɪʃən ʌvðə flˈoʊ fˈiːld kæn biː ɐplˈaɪd ɪn ˌɛni əbzˈɜːvɚz fɹˈeɪm ʌv ɹˈɛfɹəns, ænd ɪn ˌɛni koʊˈɔːɹdᵻnət sˈɪstəm jˈuːzd wɪðˌɪn ðə tʃˈoʊzən fɹˈeɪm ʌv ɹˈɛfɹəns.
However, in general both the Lagrangian and Eulerian specification of the flow field can be applied in any observer's frame of reference, and in any coordinate system used within the chosen frame of reference.