1. Overview — FDSN StationXML

1. Overview — FDSN StationXML
1.
Overview
1.1.
Introducing StationXML
StationXML is an
XML
representation of
metadata
that describes the data collected by
geophysical instrumentation.
StationXML is defined by a schema that specifies the allowable format of StationXML documents.
1.1.1.
StationXML Example
StationXML
Show/Hide

xmlns=
"http://www.fdsn.org/xml/station/1"
xmlns:xsi=
"http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=
"http://www.fdsn.org/xml/station/1 http://www.fdsn.org/xml/station/fdsn-station-1.2.xsd"
schemaVersion=
"1.2"


FAKE-DC


Some
WEB
SERVICE


2022-02-21T20:27:54.6270Z

code=
"IU"
startDate=
"1988-01-01T00:00:00Z"

Global
Seismograph
Network
IRIS/USGS
(GSN)

type=
"DOI"
10.7914/SN/IU

code=
"ANMO"
startDate=
"2002-11-19T21:07:00Z"

(GSN)
IRIS/USGS
(IU)
and
ANSS


34.94591


-106.4572


1820.0



Albuquerque,
New
Mexico,
USA


code=
"BHZ"
locationCode=
"00"
startDate=
"2018-07-09T20:45:00Z"

34.94591


-106.4572


1632.7


188




-90


40



Streckeisen
STS-6A
VBB
Seismometer





1.98475E9


0.02



m/s




count








Note that each XML element must have a start tag (e.g., ) and an end tag ()
and the element hierarchy must be maintained (e.g., a may not exist outside
of a and a may not exist outside of a , etc.).
1.1.2.
The FDSN and StationXML schema
StationXML was developed through the International Federation of Digital Seismograph Networks
FDSN
) to provide a standardized format for geophysical metadata.
Notice that the example StationXML excerpt above contains the following lines

xmlns=
"http://www.fdsn.org/xml/station/1"
xmlns:xsi=
"http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=
"http://www.fdsn.org/xml/station/1 http://www.fdsn.org/xml/station/fdsn-station-1.2.xsd"
schemaVersion=
"1.2"
The first line, the xml prologue, specifies the xml version and the character encoding.
The second line begins the StationXML document and
specifies the location and version of the schema
to which the StationXML example must conform.
The FDSN maintains all versions of the StationXML schema at:
For instance, at the time of this writing, the latest schema version is v1.2 and is
located at:
1.1.3.
Character Encoding
UTF-8 is the default encoding for XML, specified in the prologue,
allowing non-ascii characters to be used within StationXML. This
is common within names of people and places and in comments and descriptions.
However, authors should use ASCII when possible for maximum portability.
In particular, text that will likely be used by software, as opposed to simply
displayed, such as ids and units, should only use ASCII.
1.2.
Documentation Organization
This documentation has 5 parts:
This introduction
StationXML Reference - Over time, once users have absorbed the other parts of the
documentation, it is expected that this reference section will be the most frequently
used. The reference section is auto-generated directly from the FDSN schema so that it
should always be in sync with the schema.
The reference itself is broken out by the 5 levels of response detail:
FDSNStationXML
Network
Station
Channel
Response
Specifying and using response information - In this section you will find theory and examples
to help you create instrument responses for your own stations.
StationXML tools - contains examples of 3rd party tools available to help users create and edit
StationXML files. This is expected to be a fluid page that changes as new tools become
available and older tools are deprecated.
Appendices - In here you will find more technical details on specific parts of StationXML and metadata.
For instance, the first section, Mapping SEED to StationXML, is meant to be used as a reference to help
users migrate their SEED format metadata to StationXML
1.3.
Some History - SEED
For three decades, the Standard for the Exchange of Earthquake Data
SEED
) was the standard
format for archiving and distributing metadata within the seismological community.
Once representing file volumes binding metadata to data, a provision was later developed
that allowed SEED metadata to stand on its own and was given the designation ‘dataless SEED’.
StationXML was developed through the FDSN (International Federation of Digital Seismograph Networks)
as a replacement and extension of the SEED standard.
The purpose of the FDSN StationXML schema (
fdsn-station.xsd
is to define an XML representation of the most important and
commonly used structures of SEED 2.4 metadata with enhancements.
The goal of this document is to allow mapping between SEED 2.4 dataless SEED volumes and the StationXML schema with as little
transformation or loss of information as possible, while at the same time simplifying station
metadata representation when possible. Also, content and clarification has been added where
lacking in the SEED standard.
1.4.
StationXML Schema Changes
1.4.1.
Changes from version 1.1 to 1.2 (2022-2-25)
The 1.2 revision of StationXML makes no changes to the schema proper, only
changing the schema version and adding
documentation via

and

elements, as well
as external files. Any existing code that works with 1.1 should work with
1.2 without modification. We recommend that services generating StationXML
or distributing it, such as FDSNWS Station web services, update the
schemaVersion
attribute to ‘1.2’ at the next convenient opportunity.
Note that the documentation makes recommendations in many cases and services
that generate 1.2 StationXML should attempt to follow these recommendations
where possible. These recommendations include:
Dates and times should be
W3C/ISO 8601
and should always include a timezone of ‘Z’ to indicate UTC
Do not use
endDate
in the future, it should not be present when currently active
Originators of StationXML use

and distributors use

Network, Station and Channel
sourceId
should use the FDSN Source Identifiers
specification,
Use SI symbols for unit name, like
m/s
, along with singular lowercase “count” for digital counts.
Avoid SEED-style uppercase unit symbols
Omit
Description
for common units like
m/s
m/s**2
count
, etc.
Use empty
Response
element when response is unknown or not applicable.
For low pass FIR filters, use gain at zero frequency (sum of coefficients)
Gain-only analog Stages should use PolesZeros with no poles or zeros
Gain-only digital Stages should use FIR with a single numerator of value 1
1.4.2.
Changes from version 1.0 to 1.1 (2019-5-3)
(Edited 2019-12-18 for small clarifications)
Add (persistent) element to all base nodes (Network, Station, Channel)
Unify response elements, allow “number” and disallow “unit” attribute to and
Allow to be optional
Use xs:double for , and
Include data availability elements described in the fdsn-station+availability-1.0.xsd extension schema as optional elements of the main schema
Remove from
Limit each to a single
Allow more than a single occurrence in , same as in
Allow at the level, same as in
Add “sourceID” attribute, with URI value, to the base node type for ,,
Do not require and disallow and for response stages
Add “measurementMethod” attribute to “uncertaintyDouble” attribute group used by azimuth, dip, distance, latitude, longitude, elevation, etc. types
Add within and
Add “subject” attribute to to allow relating comments, make “id” attribute optional.
The vast majority of the StationXML 1.0 schema exists in the 1.1 schema, making most 1.0 documents compatible
with the 1.1 schema. There are a few small exceptions where 1.0 elements were removed from 1.1, in one
important case to avoid the specification of incorrect metadata.
An
XSLT definition for StationXML 1.0 to 1.1 conversion
exists to assist
with the systematic conversion of version 1.0 documents to the version 1.1 schema. This is done by removing the
elements no longer allowed in 1.1.
1.4.3.
Potential Future Changes
The following are potential future changes, as tagged in the schema with elements in the documentation. They may result in modifications or deletions in future versions of StationXML.
schemaVersion :
Warning, Future Change
schemaVersion: This attribute may change to be a string to allow micro versions, and potential dash, ‘-’, separators starting in version 2. Users should not assume ‘xs:decimal’.
:
Warning, Future Change
: This element is likely to be a choice with Sender.
:
Warning, Future Change
: This element is likely to be a choice with Source.
endDate :
Warning, Future Change
endDate: This attribute should not be used if it is in the future.
endDate :
Warning, Future Change
endDate: This attribute is likely to require timezone of Z.
startDate :
Warning, Future Change
startDate: This attribute is likely to require timezone of Z.
:
Warning, Future Change
: This element is likely to be removed.
:
Warning, Future Change
: This element is likely to be removed.
endDate :
Warning, Future Change
endDate: This attribute should not be used if it is in the future.
endDate :
Warning, Future Change
endDate: This attribute is likely to require timezone of Z.
startDate :
Warning, Future Change
startDate: This attribute is likely to require timezone of Z.
:
Warning, Future Change
: This element is likely to be removed.
:
Warning, Future Change
: This element is likely to be removed.
:
Warning, Future Change
: This element is likely to be removed.
:
Warning, Future Change
: This element is likely to be removed.
endDate :
Warning, Future Change
endDate: This attribute should not be used if it is in the future.
endDate :
Warning, Future Change
endDate: This attribute is likely to require timezone of Z.
startDate :
Warning, Future Change
startDate: This attribute is likely to require timezone of Z.
:
Warning, Future Change
: This element is likely to be removed.
:
Warning, Future Change
: A filter, (PolesZeros, Coefficients, FIR, etc) may be required.
:
Warning, Future Change
: The Numerator element is likely to be changed to require at least one numerator.
:
Warning, Future Change
: At least one Numerator may be required.
:
Warning, Future Change
: The NumeratorCoefficient field is likely to be changed to require at least one numerator in future versions of StationXML.
:
Warning, Future Change
: The NumeratorCoefficient field is likely to be renamed to Numerator in future versions of StationXML.
:
Warning, Future Change
: At least one Numerator may be required.
:
Warning, Future Change
: May be renamed to Numerator.
1.5.
Documentation Changes
Changes to this documentation.
Version 2022-02-25:
Resolved issues with documentation by FDSN WG evaluation team.
Version 2020-09-02:
Initial StationXML documentation.
The initial version of StationXML documentation was prepared by
ISTI
and sponsored by
IRIS Data Services
and
ORFEUS