topic Re: Field mapping in Merge Tool in ArcGIS Pro Questions

Field mapping in Merge Tool

AmeliaNewsam — Thu, 07 Feb 2019 20:47:27 GMT

I'm merging a bunch of feature classes (400) and trying to understand the Field Map settings. I need to map multiple input fields onto one output field, but I can't figure out how to do that (it looks like I have to do it for each feature class individually, which can't be right). I've read the ESRI help page, but it just didn't go into enough detail for me. If some kind soul could step me through the process, I would appreciate it. Or if there's an ESRI tutorial that would help, I'd be grateful for the title.

Re: Field mapping in Merge Tool

ColeAndrews — Mon, 11 Feb 2019 21:40:41 GMT

So the fields are different between each of the 400?

Re: Field mapping in Merge Tool

AmeliaNewsam — Tue, 12 Feb 2019 03:04:55 GMT

No, about half of the feature classes have one variation of a field name and the other have another. It should be straightforward, but I just couldn't figure out how to do it.

Re: Field mapping in Merge Tool

ColeAndrews — Tue, 12 Feb 2019 14:53:24 GMT

There may be other ways to go about it, but I would probably merge the two halves independently. Merge the ~200 with the one variation of fields, then merge the other ~200 with other variation. Then merge those 2, so you're only field mapping for 2 feature classes.

Re: Field mapping in Merge Tool

AmeliaNewsam — Tue, 12 Feb 2019 16:39:32 GMT

Oh dear, I'm afraid I don't follow. I thought you select one of the fields as your output field to map onto, and then select both of the input field variations to map onto that output field. But when you select input fields, it seems to make you do it file by file, which takes a long time for 200 files.

Re: Field mapping in Merge Tool

DanPatterson_Retired — Tue, 12 Feb 2019 17:28:41 GMT

There is no solution to this other than doing it one by one or coding a solution which would search through files to find ones which are compliments of the other and doing the field map that way. I suspect that it would take a while unless you can split the work up amongst other people or by yourself on multiple machines. I suspect that coding isn't a solution then.

Re: Field mapping in Merge Tool

AmeliaNewsam — Tue, 12 Feb 2019 17:46:39 GMT

OK, I do actually understand what you're saying now (just took a few minutes to sink in), but I still am not sure how to select the source field from all the files at once. I think I tried just selecting it from one file, and it ended up mapping only that one file. I'm sure it's just a simple thing I'm not understanding, but it's hard to communicate what that thing is.

Re: Field mapping in Merge Tool

AmeliaNewsam — Tue, 12 Feb 2019 17:48:19 GMT

OK, thanks, then I'm not crazy! You never know.

Re: Field mapping in Merge Tool

DanPatterson_Retired — Tue, 12 Feb 2019 17:48:33 GMT

that is how you map... one file at a time, there is no mention of matching one file to many in the help

Attribute field mapping—ArcGIS Pro | ArcGIS Desktop

Re: Field mapping in Merge Tool

AmeliaNewsam — Tue, 12 Feb 2019 17:50:12 GMT

So I did end up just merging without mapping and then creating a new field and calculating it differently for the two categories of features. It took a few minutes, but nothing like it would have taken to map each individually. I probably should put a little time into learning Python.

Re: Field mapping in Merge Tool

AmeliaNewsam — Tue, 12 Feb 2019 17:53:02 GMT

But it should be a simple enough thing to do, right? I mean to put that capability into the software. If it can move data from one field to another for one file, it should be a simple thing to allow it to move multiple fields. But maybe it's not something people need to do often enough to make it worthwhile for ESRI to do.

Re: Field mapping in Merge Tool

DanPatterson_Retired — Tue, 12 Feb 2019 17:56:56 GMT

Everybody's 'use-case' is unique. What is one person's main workflow isn't another's. I rarely make maps, but I use gis analytical tools extensively. And I create my tables outside of Arc* and bring them in only as needed. Coding can be a solution but it is not 'the' solution. Good luck

Re: Field mapping in Merge Tool

ColeAndrews — Tue, 12 Feb 2019 18:49:15 GMT

Field mapping is only required if you don't have common field names between the files to merge, but you want all the data in one column. You said half of the 400 feature classes had one set identical field names, and the other half had identical. Running the merge tool twice, as I described, is equivalent to what you did with the field calculator. Instead of using the field map settings when merging the two intermediate feature classes, you calculated the field back in to a common column after merging.

Re: Field mapping in Merge Tool

ColeAndrews — Tue, 12 Feb 2019 19:00:17 GMT

"it should be a simple thing to allow it to move multiple fields". You can move multiple input fields to 1 field in the field map. But you need to select them interactively, it won't automatically select the 400 fields to map to the 1 output field.

If you had 400 variations of input field names to merge, then you'd be stuck doing something like this or coding. But since you only had 2 variations, that why I would not go this route and stick with the field calc you did or the 2 consecutive merges.

See image-- you can multi select all the fields of inputs to map to 1 output field.

Re: Field mapping in Merge Tool

AmeliaNewsam — Tue, 12 Feb 2019 20:48:05 GMT

Thanks Dan!