Thread: units in quakeml/event ws

Started: 2013-03-13 21:41:20
Last activity: 2013-03-14 06:46:26
Topics: Web Services
Philip Crotwell
2013-03-13 21:41:20
Hi

The quakeml spec (1.2) says that this depth field in an origin is in meters.

depth Depth of hypocenter with respect to the nominal sea level given by
the WGS84 geoid (Earth Gravitational Model, EGM96, Lemoine et al.
1998). Positive
values indicate hypocenters below sea level. For shallow hypocenters, the depth
value can be negative. Note: Other standards use different conventions for
depth measurement. As an example, GSE2.0, defines depth with respect to the
local surface. If event data is converted from other formats to QuakeML,
depth values may have to be modified accordingly.

Unit: m

But when I query the event ws, the values that come back look like they are
in kilometers, ie 33 instead of 33000 like in this:

<origin publicID="smi:www.iris.edu/ws/event/query?originId=4908125"
iris:contributor="NEIC PDE-M" iris:catalog="NEIC
PDE"><time><value>1999-08-17T15:06:27.0700</value></time><creationInfo><author>NEIC</author></creationInfo><latitude><value>34.814</value></latitude><longitude><value>32.859</value></longitude><depth><value>33.0</value></depth></origin>


QuakeML doesn't have a "units" field, so it can't just be labeled as "m" or
"km".

Is this a bug, or is the iris ws just choosing to not follow the spec?

thanks
Philip

  • Chad Trabant
    2013-03-13 23:18:26

    Hi Philip,

    This is a bug. We will fix this in our soon-to-be-released FDSN event web service. We will probably not change the current behavior of the production service as there are likely dependencies on how we are generating it now.

    Thanks for reporting it. Somewhat surprising that it took this long to get noticed.

    Chad

    On Mar 13, 2013, at 11:41 AM, Philip Crotwell <crotwell<at>seis.sc.edu> wrote:

    Hi

    The quakeml spec (1.2) says that this depth field in an origin is in meters.

    depth Depth of hypocenter with respect to the nominal sea level given by the WGS84 geoid (Earth Gravitational Model, EGM96, Lemoine et al. 1998). Positive values indicate hypocenters below sea level. For shallow hypocenters, the depth value can be negative. Note: Other standards use different conventions for depth measurement. As an example, GSE2.0, defines depth with respect to the local surface. If event data is converted from other formats to QuakeML, depth values may have to be modified accordingly.

    Unit: m


    But when I query the event ws, the values that come back look like they are in kilometers, ie 33 instead of 33000 like in this:

    <origin publicID="smi:www.iris.edu/ws/event/query?originId=4908125" iris:contributor="NEIC PDE-M" iris:catalog="NEIC PDE"><time><value>1999-08-17T15:06:27.0700</value></time><creationInfo><author>NEIC</author></creationInfo><latitude><value>34.814</value></latitude><longitude><value>32.859</value></longitude><depth><value>33.0</value></depth></origin>


    QuakeML doesn't have a "units" field, so it can't just be labeled as "m" or "km".

    Is this a bug, or is the iris ws just choosing to not follow the spec?

    thanks
    Philip
    _______________________________________________
    webservices mailing list
    webservices<at>iris.washington.edu
    http://www.iris.washington.edu/mailman/listinfo/webservices


    • Philip Crotwell
      2013-03-14 03:22:29
      ok, sounds good. I will code for the fdsn version and assume you all work
      faster then I do. :)

      thanks,
      Philip

      On Wednesday, March 13, 2013, Chad Trabant wrote:


      Hi Philip,

      This is a bug. We will fix this in our soon-to-be-released FDSN event web
      service. We will probably not change the current behavior of the
      production service as there are likely dependencies on how we are
      generating it now.

      Thanks for reporting it. Somewhat surprising that it took this long to
      get noticed.

      Chad

      On Mar 13, 2013, at 11:41 AM, Philip Crotwell <crotwell<at>seis.sc.edu>
      wrote:

      Hi

      The quakeml spec (1.2) says that this depth field in an origin is in
      meters.

      depth Depth of hypocenter with respect to the nominal sea level given by
      the WGS84 geoid (Earth Gravitational Model, EGM96, Lemoine et al. 1998). Positive
      values indicate hypocenters below sea level. For shallow hypocenters, the depth
      value can be negative. Note: Other standards use different conventions for
      depth measurement. As an example, GSE2.0, defines depth with respect to the
      local surface. If event data is converted from other formats to QuakeML,
      depth values may have to be modified accordingly.

      Unit: m

      But when I query the event ws, the values that come back look like they
      are in kilometers, ie 33 instead of 33000 like in this:

      <origin publicID="smi:www.iris.edu/ws/event/query?originId=4908125"
      iris:contributor="NEIC PDE-M" iris:catalog="NEIC
      PDE"><time><value>1999-08-17T15:06:27.0700</value></time><creationInfo><author>NEIC</author></creationInfo><latitude><value>34.814</value></latitude><longitude><value>32.859</value></longitude><depth><value>33.0</value></depth></origin>


      QuakeML doesn't have a "units" field, so it can't just be labeled as "m"
      or "km".

      Is this a bug, or is the iris ws just choosing to not follow the spec?

      thanks
      Philip
      _______________________________________________
      webservices mailing list
      webservices<at>iris.washington.edu
      http://www.iris.washington.edu/mailman/listinfo/webservices




  • Joachim Saul
    2013-03-14 06:46:26
    Philip Crotwell [13.03.2013 19:41]:
    The quakeml spec (1.2) says that this depth field in an origin is in meters.

    Yes. It has been in meters since QuakeML version 1.1 released in 2008.

    [...]

    But when I query the event ws, the values that come back look like they are
    in kilometers, ie 33 instead of 33000 like in this:

    [...]

    Is this a bug, or is the iris ws just choosing to not follow the spec?

    If it is supposed to be QuakeML 1.1 or newer, then returning a depth in km is a bug.

    Regards
    Joachim

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