Transformations going from NAD27 to new HARN/... datums are not using HARN grid files

[baertelchen]

In changeset 1926, to fix ticket 65, new HARN-based coordinate systems, datums and transformations had been added to the dictionaries.

However, the paths dictionary hasn't been updated. This currently leads to the following transformation behavior:

• converting from LL27 to HPGN uses the NADCON/HPGN grid files.

• converting from LL27 to HARN/... uses an analytical transformation from NAD83 to HARN - but not the grid files.

Also, there's nothing wrong with the HPGN-based systems per se; i.e. they do not have incorrect parameters or so. Depending on the use case, the newly introduced HARN/... systems and datums might more appropriate.

We should fix this ticket as follows:

• move the HPGN-based systems out of the LEGACY group.

• add new geodetic paths so that transforming from LL27 to HARN/... uses the grid files.

[baertelchen]

Fixed in changeset 2143.

The main problem fixed by the submission is that the HARN/... datums where *NOT* using the HARN grid files when transforming between NAD27 and HARN.

This was due to missing path definitions. When transforming between NAD27 and HARN, the transformation bridge built on-the-fly did not pick up the individual NAD83_TO_HARN/... transformations but used the NAD83_TO_WGS84 instead.

2 fixes were included:

1) create 50+ new paths of type [HARN/XX_to_WGS84] analog to the existing [HPGN_to_WGS84] These guys look as follows:

GP_NAME: HARN/AL_to_WGS84

SRC_DTM: HARN/AL
TRG_DTM: WGS84
DESC_NM: High Accuracy Regional Network (aka HPGN) for region AL

SOURCE: Derived by Mentor Software from US NGS NADCON 2.10

XFORM: NAD83_to_HARN/AL,INV
XFORM: NAD83_to_WGS84,FWD

2) Move the HPGN-based systems out of the LEGACY group.

As stated in the ticket, the HPGN-based systems, like [VAHP-SF], are not incorrect in terms of that parameters are bad or something like that - there merely exist alternatives, like [HARN/VA.VA-SF], which might be more appropriate to use in a given context.

The systems that have been moved out of the LEGACY group have been distributed to the appropriate [USA, ...] and [UTM, HPGN Datum] categories.

Changes have been unit-tested + reviewed by Hugues.