I'm wanting to create a service area within network analyst and want to input polygons as the facilities. However, I'm having trouble with this! I can input point features into the facilities, but am unable to do so with my polygon features. Can you only use point geometry as facilities within a service area analysis?
I believe you can only use points as facilities within your service area analysis. Depending on the context of your work, perhaps you could consider using the centroid of the polygons, the intersections of the polygon boundaries with your network dataset or perhaps which junctions of the network are located in proximity of the polygons?