Transform from NAD_1983_HARN to WGS_1984

[RobertStevens]

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

to

   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?

[MelitaKennedy · Accepted solution]

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

[RobertStevens]

Ty Melita. That is most helpful.