BNO C2: GGOS Committee on

Data and Information Systems

Chair: Roger Fraser
Vice-Chair: Taylor Yates


Until recently, high precision positioning technologies have only been available for professional applications using specialised equipment (e.g. surveying, machine guidance and control track farming). Recent advancements in positioning technologies have enabled mass-market applications to achieve similar accuracies for a fraction of the cost.

GNSS paired with corrections delivered via the Internet or satellite communications, will permit national coverage of positioning services with an accuracy of several centimetres or better. This will open up a wide range of positioning applications for new industries (e.g. intelligent transport systems, location-based services, precision agriculture) and enable existing industries to improve productivity, efficiency, safety and knowledge. To support these new and existing users and maximise the data potential, it is essential that the positioning data, products and services are Findable, Accessible, Interoperable and Reusable (FAIR).


The Committee on Data and Information had two GGOS objective areas:
• Development and implementation of a portal;
• Development and implementation of a metadata scheme
Initial work on the portal was done by Bernd Richter. When he retired, the task was transferred to the GGOS Coordinating Office.
Near term Metadata activity (Carey Noll/CDDIS)
CDDIS is implementing collection-level metadata through the Earth Observation System Data and Information System (EOSDIS) Common Metadata Repository (CMR). CDDIS is an EOSDIS Distributed Active Archive Centers (DAACs) and thus utilizes the EOSDIS infrastructure to manage collection and granule level metadata describing CDDIS archive holdings; these metadata include DOIs associated with the CDDIS archive contents. The CMR is accessible through APIs and can be used in the future by GGOS to find geodetic data and products available through the CDDIS.
Longer-Term Metadata activity (Nicholas Brown/Geoscience Australia

What is GeodesyML?

The Geodesy Markup Language (GeodesyML) is a standard way of describing (encoding) and sharing geodetic data and metadata. In the same way people from all over the world speak different languages, so do geodesists. For example, some people use the term ‘GNSS station’ and others use the term ‘GNSS site’. GeodesyML is a common language. By mapping your database to GeodesyML, when your data is shared with others, it is easy for the user to discover and combine with other data.

Why does the geodetic community need GeodesyML?

The geodetic community is frequently called upon to provide data, products and services to support a broad spectrum of government, industry, science and societal applications. Coupled with this is the ubiquitous uptake across society of accurate and reliable Positioning, Navigation and Timing (PNT) information. In order to service these user demands in a robust way, geodetic data and the associated metadata need to be Findable, Accessible, Interoperable and Reusable (FAIR). The continual increase in the volume and complexity of data means we also need to generate, transfer and use data and metadata via a machine readable form. In order to achieve these stated goals it is clear that the time has come to develop a XML-based standard for geodesy.

Is GeodesyML aligned with international standards?

Yes. Recognising that despite the huge impact of geodesy on society, geodetic data is a small subset of spatial data, and an even smaller subset of Earth observation data. The developers have therefore aligned GeodesyML to existing international standards (i.e. ISO and OGC) so that data and metadata from the geodetic community aligns closely with existing initiatives in these larger communities.
For more information on this topic, please see the blog post International Standards and GeodesyML

What types of data and metadata does GeodesyML deal with?

GeodesyML currently handles geodetic data and metadata relating to equipment, site logs, measurement, adjustment, quality, monuments, reference frames and data lineage. Although GeodesyML is limited to GNSS data and metadata at this time, further development in other fields of geodesy are anticipated in the future.


Activities underway at CDDIS:

  1. Complete collection level metadata related to CDDIS data and product holdings in the EOSDIS Common Metadata Repository (CMR)
  2. Re-ingest CDDIS data holdings in order to extract granule level metadata linked to these new collection level records

Activities underway on Geodesy Markup Language (GeodesyML)

Geoscience Australia is partnering with a range of international organisations on the following projects to ensure GeodesyML meets user requirements:

1 – Improving the value of Geodetic Products
1.1: Develop and confirm GNSS value chains

• Engage with representatives from all industry sectors to develop GNSS value chain diagrams.

1.2: Identification of gaps in current standards

• To identify and address critical gaps in standards which could inhibit the uptake of precise positioning products.

1.3: Developing and distributing customised GNSS metadata profiles for industry

• Establish detailed, community-specific requirements for FAIR geodetic and positioning metadata and setup a FAIRness compliance test.
• Develop a GNSS metadata profile(s) for specific user sectors.
• Develop education material to explain how user groups can use GNSS metadata profiles.
• Engage with industry to test the GNSS metadata profile(s) for user acceptance.
• Revise GNSS metadata profile(s) based on user feedback.
• Distribute via Geoscience Australia website.

2 – Extension of GeodesyML
2.1: OGC Innovation Program

• Expand the information model of GeodesyML with required metadata for end-users.
• Revise and expand the information model of GeodesyML to ensure the provided precise positioning data is FAIR.
• Investigate applicability of OGC API for provision of precise positioning data to the end-users.
• Supervise improvement of GeodesyML and coordinate these efforts within OGC Innovation Program.
• Development, implementation and testing of GeodesyML against current standard practice

2.2: GeodesyML adopted as a community standard

• Engage with Standards Australia to develop an adoption path for GeodesyML in ISO and OGC.
• Engage with ISO and OGC to propose GeodesyML as a community standard.
Work through ISO and OGC process to respond to changes and suggestions made by ISO and OGC.