Starttime parameter confusion for station service

[nbalfour]

The FDSN specification is a bit confusing when it comes to how it deals with starttime for the station service. See this thread http://www.fdsn.org/message-center/thread/176/

The main point is the last sentence in the paragraph under Time Parameter Interpretation.
"The selection shall include any metadata epochs intersecting with the specified time range."
This implies that as long as a station's status is open at the start of the time period it should be returned.

Our current implementation of starttime for the station service only returns stations that open after or at starttime.

Can we please change the the starttime for the station service to include all stations open at starttime.

[calum-chamberlain]

👍 Just ran into this issue using what worked in #129 before, and does not work now.

[junghao]

@nbalfour
For "intersecting with the specified time range" it brings more confusion:

Consider the timeline:

The horizontal line represents the metadata active period. And query parameters are arrows below.
If there's only 1 query parameter "startTime", then:
For current implementation:
Case 1 - station included.
Case 2 - station excluded
Case 3 - station excluded

New implementation:
Case 1 - station is excluded.
Case 2 - station is included.
Case 3 - station is excluded ("not intersecting with the specified time range") -> Is this what we want?

[calum-chamberlain]

As a user, I would expect:

1. Include
2. Include
3. Exclude
   Which was (I think) what we were getting before, and I think what @megies was getting at in the link @nbalfour posted.

[junghao]

From @calum-chamberlain 's comment I think what we're expecting becomes (from the algorithm level):

Include a station if its end time is after the "startTime" query parameter.

Is that right?

[ozym]

That sounds right.

[nbalfour]

@junghao yes that is right

[junghao]

@nbalfour @calum-chamberlain
However for

1. Include
2. Include
3. Exclude

Then startTime is a duplicate for endBefore.

[nbalfour]

Check the service and it's working as excepted. Thank you.