grammar - Does Vて+いる always mean an action already completed?

For the longest time, I thought that a verb ending in て+いる meant that one was currently doing an action, similar to how we use ~ing in English to mean a contuinuing state. So 食{た}べている means "eating".

However, I've run into confusion over sentences like 日本{にほん}に来ている. I thought it meant, "coming to Japan" but apparently it actually means "came to Japan and still here".

After some looking into the issue, it seems that there is a thing in Japanese called a "punctual verb". These are actions that can not be extended or divided, so they're either done or not done. 来る it would seem, is one of these verbs, because you have either come or not. At least, as far as Japanese is concerned.

However, the matter is not entirely resolved for me. Consider this screenshot from a weather report:

Shouldn't 台風{たいふう}が日本{にほん}に来{き}ている mean "the typhoons have come to Japan and are already here"? However, according to the dates included in the image, it is clearly depicting that the typhoons are on their way, in the process of coming.

What is the dividing line between a punctual action and a continuing action, and how does one know which verbs are which?

Answer

I think the question is answered by now, but in any case I just wanted to mention that Martin’s Reference Grammar of Japanese describes three different uses for ～ている:

1. Repetitive/habitual: 学校を通っている → I usually pass through the school; I’m passing the school these days;


2. Continuative: 学校を通っている → I am passing the school right now (but haven’t passed it yet);


3. Resultative: 学校を通っている → I have passed the school (already).

You’ll need context to know which of the three meanings is intended.

Further, as other people have said, some verbs are perceived as “punctual” and don’t have the continuative (no. 2) meaning. They can still be repetitive or resultative. Such verbs include 行く、開く、来る、出る and many others.

You can read the whole section on google books: http://books.google.com/books?id=SszxbMtHbs8C&pg=PA517#v=onepage&q&f=false . There’s a list of punctual verbs on page 518.