What does it mean to be "over a law"?


I was a little confused after reading this on Wikipedia article for
[宇部港](http://ja.wikipedia.org/wiki/%E5%AE%87%E9%83%A8%E6%B8%AF), a harbor in
Ube, Yamaguchi:

> 港湾法{こうわんほう}上の重要港湾...に指定されている。

I'm really not used to reading very technical writing, so there is a (pretty
good) chance that I'm way off the mark, but I figured it means something like:

> "It is designated as an Important Port under the Harbor Act" (or however the
> legalese works out).

What got me stuck was the use of the kanji `上` (which I, for lack of a clear
reference, am reading as `じょう`). Is it saying that the `港湾法` is _above_ the
Ube Harbor, or vice-versa? It may be how English has wired my brain, but I
think of things "under a law"? Is this simply the way it's said in Japanese?
Does it have another meaning?




Without knowing the entire sentence, this looks like a `〜上` meaning "from the
viewpoint/standpoint of 〜". I talked about the meaning of this [in this
thread](https://japanese.stackexchange.com/questions/3174/jlpt-n1-question-
why-isnt-a-large-amount-of-money-a-good-enough-reason-to-kill), so I'll defer
you there for a more complete explanation.

Basically sounds like "From the viewpoint/In terms of the Harbour Act 〜".
Actually, in this case, I think "Under the Habour Act" (as you mentioned)
would be correct English also.




Without knowing the entire sentence, this looks like a `〜上` meaning "from the
viewpoint/standpoint of 〜". I talked about the meaning of this [in this
thread](https://japanese.stackexchange.com/questions/3174/jlpt-n1-question-
why-isnt-a-large-amount-of-money-a-good-enough-reason-to-kill), so I'll defer
you there for a more complete explanation.

Basically sounds like "From the viewpoint/In terms of the Harbour Act 〜".
Actually, in this case, I think "Under the Habour Act" (as you mentioned)
would be correct English also.

