Kernrechtsfrage
Whether the billboard structures are subject to setback requirements as buildings or installations under cantonal planning law.
Extrahierter Entscheid
The cantonal court could, without arbitrariness, classify the non-covered billboard structures as small buildings and apply setback rules.
Extrahierte Begründung
The Federal Supreme Court found the broader interpretation of the building concept defensible; the challenged structures were not exempt merely because they lacked a roof.