Polygon symbology options in ArcGIS Online
Hello everyone,
i have a problem with applying symbology to a polygon feature layer in ArcGIS online and was hoping to get some help.
I want to add a layer to my webmap containing university campuses of my city. The problem is, that the university buildings are scattered across town and from a large scale its impossible to make out all buildings that belong to any given school. This is especially problematic when there is a single institute isolated somewhere off the main campus.
In ArcGIS Pro I kind of solved this by using the proportional symbols symbology and drawing a large transparent circle around each building while using the background color to fill the polygons. On large scales this results in a sort of heatmap which indicates where university buildings are located. On smaller scales the circles disappear into the building outlines.
Needless to say, this does not work in ArcGIS Online, the symbology I applied in ArcGIS Pro doesnt carry over and the only option I found directly in ArcGIS Online was to fill polygons.
In order to publish a useful map I need to apply something similar as I did in ArcGIS Pro, does anyone have an idea what would allow me to do this without resorting to use duplicates with different symbologies (I want these layers to only have a single on/off switch in my webapp)
Thanks in advance, and have a great sunday everyone 
