Can't Convert Maritime Province data to WGS84

[Norm Olsen]

The three Maritime Provinces of Canada adopted ATS77 (probably in 1977 :), and never adopted what was called NAD83 in the rest of Canada. The Maritime's did, however, adopt CSRS along with the rest of Canada in 1997. Having skipped NAD83 (ala WGS84) there is no "official" means to convert data in the Maritime provinces to WGS84.

This capability is required by some applications.

[Norm Olsen]

The problem referred to in this ticket is due to the fact that three new datums were created for Nova Scotia for the sole purpose of forcing the use of a Nova Scotia specific grid data file whose coverage overlaps other grid data files referenced to the same datum. Specifically, in the Maritime Provinces of Canada, there are three provinces which have their own grid files which (due to the geography) all overlap significantly. Thus the three new datums were invented, are referenced by Nova Scotia specific CRS's, and have Nova Scotia specific geodetic transformations which reference the Nova Scotia specific grid data files. All is well. right?

The original implementation of the Nova Scotia specific datums omitted references to non-specific datums such as WGS84. Thus, conversion of Nova Scotia coordinates to, for example, WGS84 failed. This submission provides three new geodetic transformations, each of which is the NULL transformation, but which associate each of the Nova Scotia specific datum with its corresponding non-specific datum. Additionally. geodetic paths are provided so that the conversion to/from WGS84 and other datums can be accomplished.

This submission produced revision 2818.