Append sub-layers to an existing hosted feature service

Summary

The following workflow outlines how to consolidate sub-layers into a single hosted feature service, regardless of the feature class.

Instances where this may be applicable:

• Multiple feature services containing sub-layers need to be merged while retaining the sublayer structure.
• More sub-layers need to be added to an existing hosted feature layer.
• Sub-layers of varying feature classes need to be compiled into a single hosted feature service.

Workflow environment/s:

• ArcGIS Online
• ArcGIS Pro

Cause

Under the ArcGIS Online web interface, sub-layers cannot be added to existing hosted feature layers. These sub-layers may have been manually set and specified when originally creating the feature layer, however, additional sub-layers cannot be added once the feature layer has been established.

Procedure

In this example, an ArcGIS Online hosted feature layer with four (point) sub-layers Original_Numbers, shown below, and a hosted feature layer with three (point) sub-layers More_Numbers are combined into a single hosted feature layer.

1. Export both hosted feature services to a file geodatabase in ArcGIS Online.
   • The Export button is located on the vertical right pane of the item Overview page. If this button is not visible by default, select the show more toggle to expand the full dropdown list of buttons in the pane.

2. Download the file geodatabases to the device being used.
   • Be sure to "unzip" the files after they are downloaded!

*Repeat steps 1-2 if multiple hosted feature services with sub-layers are being applied.

3. Import the sub-layers from the downloaded file geodatabases.
   1. Open ArcGIS Pro and sign in to a supported account. 
   2. Open a new project.
   3. Navigate to the Map tab at the top of the screen. In the Layer section, select the dropdown arrow for Add Data and then Browse. This allows searching the device for the file geodatabase(s) that have been downloaded and unzipped.

4. Once the file geodatabase from the first layer has been located, open it and select the file geodatabase feature classes and tables.
   • If there are many file geodatabase feature classes and tables present here, choose to select them all by selecting the top entry, holding down the Shift key, and scrolling down/selecting the bottom entry.

5. Repeat the steps 3c and 3d above until all unzipped file geodatabase feature classes and tables have been added to the Contents pane. They may be listed as individual layers and standalone tables.

Note: 
The order in which the layers appear in the Contents pane correlates to the order they will be listed in the final, published hosted feature layer. If applicable, you may choose to re-arrange this order by selecting each layer in the Contents pane and dragging them to the appropriate position.
• For example, the screenshot above depicts the layers from top to bottom in order "six, seven, five, two..." You may wish to re-arrange the layers to be listed in order "one, two, three, four..." instead.

4. Publish as a web layer.
   1. Making sure Map is selected in the Contents pane, navigate to the Share tab, Share as section, select the dropdown under Web Layer, and select Publish Web Layer.

2. Specify the Name, Layer Type, Sharing Level, and other parameters of interest. For more information on this tool, refer to: Share a web feature layer
3. Under Finish Sharing, select Analyze to review any potential publishing issues.

Tip: 
When selecting the Analyze button to review for potential issues, the following error message may appear "00374: Unique numeric IDs are not assigned". To automatically assign these IDs sequentially based on their order in the Contents pane: hover over the error message, select the three dots "Options" icon, and Auto-Assign IDs Sequentially.

4. Select Publish to publish the layer. Depending on the layer sizes and amounts, this may take some time to complete.
• Once the completion message is displayed, the final hosted feature layer should be reflected in the ArcGIS Online organization's Content with all the sublayers included.