topic Re: Transform from NAD_1983_HARN to WGS_1984 in Geoprocessing Questions

Transform from NAD_1983_HARN to WGS_1984

RobertStevens — Fri, 20 Dec 2019 17:40:02 GMT

I have a number of featureclasses using the projected coordinate system

NAD_1983_HARN_StatePlane_Oregon_North_FIPS_3601_Feet_Intl

which uses as a geographic coordinate system (GCS)

NAD_1983_HARN

I am trying to convert these using the Project tool in the ArcMap toolbox

WGS_1984_Web_Mercator_Auxiliary_Sphere based on GCS_WGS_1984

When I use the tool it suggests using the transformation named

NAD_1983_HARN_To_WGS_1984_2

In ESRI's documentation (https://support.esri.com/en/Technical-Article/000005929)

it says never to use the transformation

NAD_1983_To_WGS_1984_2

It is a bit confusing. These two transformations, one from 1983_HARN, the other without the _HARN in the name,

are they completely different transforms? Is that the best transformation to use in Oregon, North?

Re: Transform from NAD_1983_HARN to WGS_1984

MelitaKennedy — Fri, 27 Dec 2019 22:22:33 GMT

Completely different transformations. NAD 1983 HARN is a re-adjustment (improvement) of NAD 1983. NAD_1983_To_WGS_1984_2 is not recommended because its area of use is for the Aleutian Islands. I think I've seen specific Aleutian Island data once or maybe twice in the 25 years I've worked at Esri.

Use NAD_1983_HARN_To_WGS_1984_3 over NAD_1983_HARN_To_WGS_1984_2.

Melita

Re: Transform from NAD_1983_HARN to WGS_1984

RobertStevens — Fri, 27 Dec 2019 23:03:55 GMT

Ty Melita. That is most helpful.

Re: Transform from NAD_1983_HARN to WGS_1984

PSRFA_GIS — Tue, 21 Oct 2025 18:18:28 GMT

It looks like this is still relevant, can you confirm Melita (transformation expert!) I see some ITRF00 options now, not sure if those supercede NAD_1983_HARN_To_WGS_1984_3 ?

Re: Transform from NAD_1983_HARN to WGS_1984

KingCounty_GIS_ET — Thu, 02 Apr 2026 20:26:15 GMT

I'd also like confirmation if NAD_1983_HARN_To_WGS_1984_3 is still the correct transformation to use or should we switch to NAD_1983_HARN_To_WGS_1984_(ITRF00)?

Our data is in NAD_1983_HARN_StatePlane_Washington_North_FIPS_4601 (US Feet). Also, when switching back to EPSG:2926, should we use WGS_1984_(ITRF00)_To_NAD_1983_HARN?