What should the NTv2 transformation grid be used for?
The appropriate NTv2 transformation grid to use differs depending on the jurisdiction and the accuracy and lineage of the dataset being transformed. Basic recommendations are listed in Table 3.4 of the Geocentric Datum of Australia 2020 Technical Manual, but if in doubt individual jurisdictions should be consulted for specific advice.
Are there any national transformation grids for AGD?
These files transformed from either AGD66 or AGD84 to GDA94, depending which version of AGD was previously adopted by that jurisdiction. Subsequently, combined grids were produced and ultimately two national transformation grid files (one each for AGD66 and AGD84) were developed.
Where can I find the conformal + distortion grid?
Conformal + Distortion: incorporates the conformal 7 parameter transformation plus localised and regional distortion revealed by incorporating coordinates on ground survey control networks across the nation. When produced, the grids will be downloadable from the ICSM GitHub transformation grid repository.
Where can I find a Canadian transformation grid?
All grids referred to below are available from the ICSM GitHub transformation grid repository in the widely used Canadian National Transformations version 2 (NTv2) format and provided under CCBY 4.0. ICSM is currently developing two 2D national transformation grids:
Is the AGD66 file in NTv2 format?
The AGD66 national file also covers the offshore areas out to the Exclusive Economic Zone (EEZ). Although still in NTv2 format, a simple conformal transformation was used to generate the shifts in these offshore areas.
What is the NTv2 datum shift for GDAL?
AGD 1966, AGD 1984, NAD83 (HARN), Cape, Lisbon, Datum 73, DHDN, Corrego Alegre 1961, Corrego Alegre 1970-72, NZGD 1949 and OSGB36. Note: See TracTickets for help on using tickets.