" Undefined geographic transformation"

[JulianeStruve]

Dear Forum,

I am trying to add data to an existing project. They do not align. When reprojecting the new file I get the error message: Undefined geographic transformation.

I am using ArcGIS 10.

Thanks  for any suggestions.

Juliane


Old file:
Projected: NAD_1983_UTM_Zone_17N
Geographic:GCS_North_American_1983

New file:
Projected: NAD_1983_CORS96_UTM_Zone_17N
Geographic: GCS_NAD_1983_CORS96

[MelitaKennedy]

Hi,

Normally, I would recommend that if the two layers are overlaying reasonably well, to ignore the difference coordinate systems. If you want to update the coordinate system of one layer, use the Define Projection tool, or add both to ArcMap, set the data frame to the coordinate system you want and right click the other layer in the table of contents and select data, export data (pick the use-the-data-frame option).

However, the differences between NAD 1983 and CORS96 should be relatively small--about a meter at most. How much of a difference are you seeing? If it's more than that, something else like an incorrect coordinate system definition may be happening.

Melita

[JulianeStruve]

Hi Melita,

thank you very much for your suggestion. I cannot get this data set into my map at all, and I suspect that there may be something wrong with it. I have since found another data set with the same information from a different source and managed to map the data without any difficulty using your answer.

Thanks a lot !

Juliane