Why am I required to have a basemap in a map I am sharing to ArcGIS Online as a web map? Maybe I don't want to include a basemap. Maybe I want to have all the layers in the map served as feature layers. Maybe I want to use my local coordinate system instead of the WGS 84 Web Mercator Auxiliary Sphere coordinate system. I have found this requirement extremely frustrating.
I even tried to create my own empty basemap. That did not work. A basemap in an ArcGIS Pro project must include a layer. So I added a single layer and then turned it off so it appears empty. That seemed to work but when I tried to open the web map in ArcGIS Online's Map Viewer, I get an error about a non-valid basemap and the web map will not open.
Please allow me to publish a web map without a basemap!!!!!!!