MerakSpielman said:
But what does it mean to know the exact location? Do they use longitude and latitude in your campaign?
Scrying works to teleport to a location - but how? If you scry an enemy, and see him in a paticular room, you can teleport to that room without having any idea where the room itself is located.
You know before casting teleport that the ship is in the middle of the ocean. Yet, by the RAW, scrying it first should help, even though most open ocean looks pretty much like any other. Why is this?
You are attempting to ask the question "How does the magic work?".
The answer to this question is irrelevant.
The real question you should be asking is "What happens under xyz circumstances?".
The Teleport spell states:
"This spell instantly transports you to a designated destination"
and
"You must have some clear idea of the location and layout of the destination."
and
"“Studied carefully” is a place you know well, either because you can currently see it, you’ve been there often, or you have used other means (such as scrying) to study the place for at least one hour."
This means that you must know the layout of where you are going. Plus, you must basically know the location of where you are going.
Both of these elements are required as per the Teleport spell. How you gain the information on layout and location and how the Teleport spell uses that information is basically irrelevant.
What is relevant is that you must have these two pieces of information. Now typically, Scrying does not give you location information, just creature and surrounding area (10 feet radius) information (i.e. layout information). However, the Teleport spell explicitly states that Scrying can be used, hence, this is an exception to how Teleport normally works. The information gained by the Scrying is sufficient enough for the location information required by Teleport.
Now, for a non-moving destination where you have been there before, you already know location and you probably have a good idea of layout (unless it has drastically changed).