Does field order matter? Maybe …

I ran into an issue the other day where my pop-ups for a utility layer in my Field Maps app stopped working. Even worse, the Classic Map Editor in ArcGIS Online would no longer let me edit the pop-ups for that feature service. The new Map Editor would, but the pop-up still didn’t display. First I needed to know what caused this, and next I needed to know how to fix it.

After doing some research and consulting with a friend in Yakima, Washington, I discovered the issue may be that my fields were in the wrong order. Rearranging the fields solved his problems. But why would that matter??

If you look at a new feature class freshly minted, it will have the Object ID (or global ID) and the Shape fields at the top, then any user defined fields you may have added, then Shape_Area and/or Shape_Length at the bottom. When you add new fields to an existing feature class, it puts the layers below the Shape_Length field at the bottom. Does it matter?

I can’t say for sure that the field order matters because I have lots of feature classes that have become ArcGIS Online feature services with fields out of order and nothing has ever gone wrong with them.

However, my utility layer had the fields out of order and the second I fixed it the utility layer started working correctly again – the pop-ups could be edited in ArcGIS Online and the Field Maps app would show them again. Field order is the only thing that changed. And when I mentioned this to a few friends of mine, they said they had experienced the broken pop-ups before with no solution and wound up rebuilding the layer.

So I can’t confirm that this is a cure-all for your pop-up issues, but it can’t hurt to try. I also noticed that if I take a feature class with the fields out of order and export to a new features class, IT FIXES THE ORDER! Why would it do that if it didn’t matter?

The conclusion seems to be that whenever possible try to keep the ID and Shape fields at the top of your fields list, all your user defined fields in the middle, and the Shape_Area and Shape_Length at the bottom of the list. If you add more fields, drag them up the list above the Shape_XXX fields. You might even try the Feature Class to Feature Class tool to make a copy and see what it does to field order. The copy might need to become the primary file. If you do this and it fixes a problem, please let me know.