Are Australian NTv2 data files compatible with North American files and software?
The files of coordinate shifts conform to the Canadian format known as National Transformation version 2 (NTv2). The Australian NTv2 transformation files are available as binary files from the GDA Technical Manual. Free software provided by ICSM jurisdictions can readily convert them to ASCII format as well as carry out the transformation process. An in-depth explanation of the format can be found in Appendix C of the Victorian GDAit (Lands Vic) or GDAit (Melbourne University) GDAit Users Manual. In the NTv2 format, south latitudes are stored as negative values, but for ease of operation in North America, western longitudes are stored as positive values. To maintain compatibility with NTv2, Australian distortion grid files store the(eastern)longitudes as negative values.
