Data Conversions / NAD Data Conversions
In 1997, the Canadian federal government developed a distortion model of shifts, which related the movement in coordinate values between the NAD27 datum and the NAD83 datum. Most conversion applications were developed to be applied against an ASCII file of coordinate pairs or else against a DXF format of a graphic/CAD file. The conversion methodology developed and used by the Province of Alberta was very inefficient for use with graphic/CAD files. Instead, MNC used processes; developed by Newby Engineering for performing the conversions of CAD files for database records.
Prior to converting NAD27 files to the NAD83 datum, all the data had to be geodetically correct, all projections known and consistent within the datasets, coordinate values could not be truncated, and there could not be any significant positional differences or errors in the datasets.