[IGSMAIL-4829]: XML for Geodesy Web Page

[Yehuda Bock]

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IGS Electronic Mail      05 Feb 08:55:46 PST 2004      Message Number 4829
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Author: Yehuda Bock, David Malveaux, Brent Gilmore, Michael Scharber

We are pleased to announce the creation of a new page "XML for 
Geodesy" on the SOPAC Web Site. The first product is an XML Schema 
definition for GPS/GNSS site metadata (i.e., "Site Logs"), as a 
possible alternative to current "human readable" approaches. We all 
know and have experienced the difficulty in achieving accurate and 
timely site metadata, and that site metadata are the most basic 
backbone elements on which subsequent data, data products, and data 
interpretations rely. This is why we have tackled this aspect first.

The XML Site Logs Schema definition is open for public review and 
comment at http://sopac.ucsd.edu/projects/xml/. The SOPAC database is 
now able to produce on demand XML-Encoded site logs, which contain 
the full content of IGS Site Logs. Please try this out at 
http://sopac.ucsd.edu/scripts/dbXMLSiteLog.cgi.

The XML schemas developed by SOPAC exist as a set of modular 
components one can use to construct other schemas for more specific 
applications.  These components (sub-schemas) currently encompass a 
variety of information pertaining to GPS (and other GNSS) stations or 
monuments (i.e. location, identification, contact agency, etc), GPS 
equipment (i.e. receiver, antenna), and GPS field surveys.  The IGS 
Site Information Log schema for instance, is broken into four 
separate XML namespaces: equipment, contact, possible interferences, 
and monument information.  These sub-schemas, along with the schema 
components used to create them, are available from 
http://sopac.ucsd.edu/ns/ and will be part of our plans to construct 
a public XML schema repository for data models associated with 
high-precision geodesy.

In turn, the repository will serve as a launch pad for a variety of 
development related to a number of future projects, with 
participation from other agencies and individuals fully welcome. 
Properly implemented, and utilized, this repository will help 
eliminate the problem of duplicated work across different agencies, 
and allow XML developers in the GPS community to build other schemas, 
either manually or on-the-fly using XML-oriented tools like XSLT 
(eXtensible Stylesheet Languages Transformation) and XPATH (XML Path 
Language) to support future applications.

We are anxious to get feedback from other GPS archives and groups on 
our particular design of the XML metadata schema, so that we can 
achieve community consensus. The GPS metadata schema bundle can be 
obtained at http://sopac.ucsd.edu/projects/xml/metadataSchema/.

Members of SCIGN's NASA REASoN CAN project, a collaboration of JPL, 
SIO, and USGS are reviewing the metadata schema. Other XML schemas, 
for example, for position time series and SINEX files are being 
developed under the NASA project and will be made available for 
public comment as they mature.

-- 
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Yehuda Bock		e-mail: ybock at ucsd.edu
Research Geodesist	Phone:  (858) 534-5292
& Senior Lecturer	Fax:    (858) 534-9873
			WWW:    http://sopac.ucsd.edu/; http://csrc.ucsd.edu/

Director, Scripps Orbit and Permanent Array Center (SOPAC)
Director, California Spatial Reference Center (CSRC)

Address:
University of California San Diego
Institute of Geophysics and Planetary Physics
9500 Gilman Drive  DEPT 0225
La Jolla, CA 92093-0225

FedEx Address:
Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics
Scripps Institution of Oceanography
8785 Biological Grade, Room 4208
La Jolla, CA 92037
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