Roman or gaulic: Orientation as a footprint of cultural identity?

The towns of Aventicum (Avenches, Switzerland) and Augusta Raurica (Augst, Switzerland) were the main Roman towns of the Civitas Helvetiorum in the province of Gallia Belgica (and later shifted to Germania Superior). Both were probably founded ex-nihilo, the first at the time of Claudius (mid first century AD), the second by Caius Munatius Plancus around 44 BC and was refounded soon after the 15 BC. The layout of both towns conforms to all Roman standards with an urban grid in orthogonal shape and with several public buildings to hail the splendor of Roman society. Also the orientation of such grid seems to conform to most Roman standards. The archaeoastronomical study of both towns is contextualised following two paths. Firstly, we consider the orientation of the layout of some other regional Roman foundations as Vesontio (Besancon, France), Iulia Equestris (Nyon, Switzerland), Forum Claudii (Martigny, Switzerland), and Vindonissa (Windisch, Switzerland). Secondly, we realize that the sacred areas (including temples, sanctuaries and often theaters) of this two towns seem to break the general layout in both of them: these appear to bear orientations skewed several degrees with respect to the general grid. In both cases a Roman theater seems to feature some kind of relation with the temple as in other areas in the Roman Empire. Notably, the orientation of these temples share similarities to other sacred precincts in the region possibly built prior to the Roman conquest. This duality in orientations, with a grid with an orientation different to that of some of the main public buildings may be a witness to a period when a compromise, negotiation, or resistance either implicit or explicit, took place between conquered and conquerors. Interestingly, similar cases have recently been reported in the Roman towns of Augusta Treverorum (present day Trier, Germany) or Augustodum (modern day Autun, France).