International Federation of Digital Seismograph Networks

Thread: append Z on query time parameters

None
Started: March 10, 2017, 2:22 p.m.
Last activity: March 20, 2017, 10:04 p.m.
Philip Crotwell
March 10, 2017, 2:22 p.m.
Hi all

If/when there is a revision to the FDSN ws spec, I think it should
allow the appending of a Z to signify UTC to all input time
parameters. Currently there is no timezone on the times and they are
limited to:
YYYY-MM-DDTHH:MM:SS.ssssss
YYYY-MM-DDTHH:MM:SS
YYYY-MM-DD

This would change to time parameters being expressed as one of these,
with the first 2 being preferred.

YYYY-MM-DDTHH:MM:SS.ssssssZ
YYYY-MM-DDTHH:MM:SSZ
YYYY-MM-DDTHH:MM:SS.ssssss
YYYY-MM-DDTHH:MM:SS
YYYY-MM-DD

The reason for this is that it is annoying to have a valid ISO
formatted UTC time and then have to delete the last character in order
to use it in a fdsn ws URL.

I am not sure if it should be mandatory, but outputting times with the
"Z" within QuakeML and StationXML output from the web services would
also be very helpful. I do not want to admit to the number of times I
have been burned by the fact that most time parsers assume local time
if the Z is not present. Having the service always use times with Z is
a relatively simple way to prevent a whole bunch of hard to track down
errors.

thanks
Philip

  • Philip Crotwell
    March 10, 2017, 2:23 p.m.
    Hi Tim

    Can you add this one to your agenda?

    thanks
    Philip


    On Fri, Mar 10, 2017 at 2:22 PM, Philip Crotwell <crotwell<at>seis.sc.edu> wrote:
    Hi all

    If/when there is a revision to the FDSN ws spec, I think it should
    allow the appending of a Z to signify UTC to all input time
    parameters. Currently there is no timezone on the times and they are
    limited to:
    YYYY-MM-DDTHH:MM:SS.ssssss
    YYYY-MM-DDTHH:MM:SS
    YYYY-MM-DD

    This would change to time parameters being expressed as one of these,
    with the first 2 being preferred.

    YYYY-MM-DDTHH:MM:SS.ssssssZ
    YYYY-MM-DDTHH:MM:SSZ
    YYYY-MM-DDTHH:MM:SS.ssssss
    YYYY-MM-DDTHH:MM:SS
    YYYY-MM-DD

    The reason for this is that it is annoying to have a valid ISO
    formatted UTC time and then have to delete the last character in order
    to use it in a fdsn ws URL.

    I am not sure if it should be mandatory, but outputting times with the
    "Z" within QuakeML and StationXML output from the web services would
    also be very helpful. I do not want to admit to the number of times I
    have been burned by the fact that most time parsers assume local time
    if the Z is not present. Having the service always use times with Z is
    a relatively simple way to prevent a whole bunch of hard to track down
    errors.

    thanks
    Philip

  • Joachim Saul
    March 20, 2017, 10:04 p.m.
    Philip Crotwell wrote on 10.03.2017 20:24:
    YYYY-MM-DDTHH:MM:SS.ssssssZ
    YYYY-MM-DDTHH:MM:SSZ
    YYYY-MM-DDTHH:MM:SS.ssssss
    YYYY-MM-DDTHH:MM:SS
    YYYY-MM-DD

    The reason for this is that it is annoying to have a valid ISO
    formatted UTC time and then have to delete the last character in order
    to use it in a fdsn ws URL.

    Important point and related to a request from a couple months ago [1]. Since the times have to be UTC by definition anyway, an ISO UTC time including the trailing "Z" should at least be acceptable as parameter. This change only requires minor modifications on the server side and should be easy to implement in a rather short time.

    Thanks for bringing this up again.

    Cheers
    Joachim


    [1] http://www.fdsn.org/message-center/thread/464/