FIG Commission 5 - Positioning and Measurement

Working Group 5.2
3D Reference Frames

Policy Issues

  • Work to bring together all organisations involved in defining or using reference frames to develop common approaches and avoid duplication. Such organisations include FIG, the International Association of Geodesy (IAG), UN-GGIM, ISO, groups of national mapping agencies, and other influential national agencies.
  • Continue the existing co-operation with IAG on the Regional Reference Frame Projects such as AFREF, APREF, EUREF, NAREF, and SIRGAS.
  • Develop and expand upon the relationships with UN-GGIM’s Sub-Committee on Geodesy (UN-SCOG), the UN SCOG WG’s, and the various UN-GGIM regional bodies.
  • Consider options for the development and implementation of 4 dimensional datums that incorporate the effects of plate tectonic and regional effects such as those due to earthquakes or local effects such as landslides.
  • Provide background technical information on relevant issues written in a way that is accessible to surveying practitioners.
  • Examine how surveying practitioners can access the reference frame, through less emphasis on networks of ground monuments and more emphasis on Global Navigation Satellite Systems (GNSS) base stations.
  • Provide information on the maintenance of CORS networks to ensure long-term stability


Nic Donnelly, New Zealand


What we are working on -

  • Review of Reference Frames in Practise Manual
  • Connection to ISO-TC211: Geodetic Registry Network.
  • FIG Publication on ITRF
  • Publication regarding national datums (different types)

What's New

The working group has continued its strong focus on accounting for geodynamics within 3D reference frames. This has involved close collaboration with our counterparts in the International Association of Geodesy 's deformation modelling working group led by Richard Stanaway. Of particular note is work undertaken on two potential formats for deformation models in which working group members have been involved. One is based on GeoTIFF and the other is based on the HDF5 format. Work is now underway to implement the GeoTIFF format into the PROJ open-source software stack. This will provide an implementation that other software vendors may also be able to leverage. Having an internationally agreed format for deformation models is becoming more urgent as many nations actively pursue datum modernisation programmes.

In terms of outreach, the main focus was the Reference Frames in Practice workshop held in conjunction with the 2019 Working Week in Hanoi. This featured two days of presentations and seminars and included good engagement from the local Vietnamese geodetic community. Further workshops are planned for later in 2020 (in conjunction with the SIRGAS meeting) and for the 2021 Working Week.

Work has commenced on a revised edition of FIG publication No. 64, Reference Frames in Practice Manual. The aim is to have this complete towards the end of 2020. Amongst other things, the manual will be updated to include information about the latest global reference frames, the UN-GGIM Global Geodetic Reference Frame and additional national case studies.