I am trying to find ways to join existing polygon feature layer with new data. For example, Esri has a living atlas reference layer for US state boundaries: https://www.arcgis.com/home/item.html?id=99fd67933e754a1181cc755146be21ca
This layer also has some population data for each state. I want to create a new polygon feature layer that is essentially a fork of this one. I then want to add some data - in this case, voter turnout data for each state. That data comes in excel format here (source http://www.electproject.org). Once I have a copy of the states polygon feature layer with the new election data, I can create some nice visualizations. I am trying to create a 2020 version of this feature layer: US Voter Turnout 2016. But I am having a hard time figuring out how to create and serve a layer from my own account that is a fork of that initial layer, and then add to it.
I have tried going into the Content section of arcgis online, hitting 'create', and creating a feature layer from an existing URL, using the arcgis server URL of the states boundaries item. When I go through the form and hit 'Done', I get this error:
Unable to add feature service definition. The operation failed because an index or statistics with name 'insights_fl_tauCNbQYU1nWzn8S' already exists on table 'user_72472.lklklkj_USA_STATES_GENERALIZED'.
I have also tried going into the original boundaries layer, and exporting the data to an excel file. Then I can add my new data as new columns. Then when trying to create a new layer, I go to create a new Polygon FeatureLayer. I hit 'Update Data', and then 'Append Data to Layer'. I try to upload the excel file, but it gives the error:
No compatible layer was found in the uploaded file. Please check your file and try again.
I feel like this should be relatively simple to do but I'm struggling to find a way, or any documentation on how to do this.