Merge error of different data type, but data types are the same

[MelissaDaniels1]

I'm trying to merge 23 line feature classes. For reference, they are all from the same source, the National Hydrography Dataset. They are all the same type: lines. When I tried to merge all of them, I got an error that says: "ERROR 002949: The data type of NHDFlowline is not the same as that of previously entered datasets."

I figured maybe one of the feature classes has an error, so I tried multiple merges with different pairs of feature classes. They all got the same error.

I tried writing to a shapefile instead of a feature class. Got the same error.

I can't find any documentation on that specific error. They're the same type, so I'm not sure what the issue is. I have merged NHD line data many times and have never had this issue. 

I tried restarting ArcGIS Pro and restarting my computer.

[Amadeus111]

Check this if helps any https://support.esri.com/en/technical-article/000012642

[MelissaDaniels1]

I removed all fields from the Field Map and ran again. That did not seem to help, so I don't believe the error is with any conflicting fields.

[KristalWalsh]

Hi, have you tried merging them a few at a time to identify where the problem dataset might be? I have not manipulated hydrography data in quite a while, but I would look to see if there are any properties defined by the dataset like scale that might cause a problem or set one apart from another. Kristal

[MelissaDaniels1]

Yep, I mentioned this in the post, but it may have been unclear. I tried merging a few different pairs, but none of them worked. So it's not an issue with just one of the datasets, but it seems to be either all of them or my merge tool.

[curtvprice · Accepted solution]

I would check to see if the inputs all have M and Z enabled (or not). Something to try is to copy to an intermediate working file geodatabase and try to merge the output. 

These datasets can be really detailed so I recommend creating a empty template dataset (using Create Feature Class) and running Append to avoid introducing domain/resolution changes.

[MelissaDaniels1]

I added them all to a new geodatabase and then merged them. That seemed to work. Thanks so much for the input!

[wayfaringrob]

Hm, this also happened to me with NHDFlowline, must be something up there. Maybe it's the vertical coordinate system? There's no environment for that in the Merge tool. Clicking the error brought me to a general Esri support page with no information.

What worked for me after setting up a new feature class was using the source layers (from the disk) in the append tool and setting the expression that way rather than using the definition queried version in my map. I found that when I dragged them over from the map, they had null geometry on output (e.g. showed up in the table, but not the map - maybe because I had my symbol layers shut off?). I didn't need to make intermediate copies first.