This page describes some publications (including whitepapers and reports) which North Road have written, and includes links to download the corresponding documents.
On GDA2020, PROJ 6 and QGIS: Lessons learnt and recommendations for handling GDA2020 within geospatial software development
A whitepaper commissioned by the ICSM (Intergovernmental Committee on Surveying and Mapping) which outlines recent software developments related to the adoption and use of the GDA2020 coordinate reference systems.
GDA2020 (Geocentric Datum of Australia 2020) is a modernization of Australia’s spatial datum, replacing the prior GDA94 standard. GDA2020 adoption requires significant updates and changes in the way geospatial software applications transform coordinates in order to ensure accurate results.
ICSM has been able to leverage the independent work done by the PROJ library maintainers as part of the “GDAL SRS barn raising effort”, and has funded investment into the QGIS Desktop GIS application to utilise this work and ensure that users of the application have an accurate and easy to use experience with GDA2020 related data.
This paper is targeted to managers and developers of spatial software projects, who have at least a background understanding of geospatial and datum concepts. It describes the motivation behind the software changes, and outlines the recommendations from QGIS software developers which other software applications may follow in adapting their software for GDA2020 compliance.
Specific recommendations are:
- Always use registered authority identifiers and codes when handling, storing, and retrieving Coordinate Reference System (CRS) objects, and avoid other representations of CRS parameters such as “proj” strings.
- Application installers should include the proj-datumgrid-oceania grid transformation files by default, or provide an easy to use method for users to install these, without requiring administrative permissions.
- Applications should explicitly advise users when grid transformation files would result in a more accurate coordinate transform, yet they are not available for use on their system – avoiding any prerequisite knowledge of the use or the existence of these files on the user’s behalf.
- Wherever possible, the desired area of use for coordinate transformations should be specified a-priori when constructing coordinate transformation operations
- Applications should provide a user-friendly means for knowledgeable users to manually override the default transformation operations applied when converting to or from GDA2020 coordinates.
Read the full whitepaper here.
Handling of 4D coordinates in desktop GIS
(Joint reported written by North Road and Mercury Project Solutions)
Following the rollout of the GDA2020 coordinate reference system, the next step for ICSM’s datum modernisation initiative is the implementation of a dynamic, time dependent datum, known as the Australian Terrestrial Reference Frame (ATRF).
It will be increasingly important to understand that latitude and longitude coordinates do not define a unique location unless the related time stamp is also identified. At best, a coordinate without datum is ambiguous and may even be meaningless. In 2020, the dynamic datum will establish a different kind of location reference system that will continually model the movement of the Australian continent.
The new dynamic (ATRF) datum will bring with it the need to create and work with time-tagged coordinates. New processes and tools to collect, manage, integrate and disseminate spatial information will therefore be required. This is in addition to, and cannot be seen separate from, the implementation of the new static datum, GDA2020, which is currently under way.
For a successful implementation, geospatial software will need to be able to manage and transform dataset with a time dependent (4D) datum. This report details the current state of 4D coordinate transformation standards and software support, and outlines the specific business requirements for handling 4D coordinate data within desktop GIS systems.
Read the full report here.