Two localities, Tamnum and Novioregum , remain to be located. When the unknown point is framed by well identified stations, one can, starting from the last point, to trace on the map, with a curvometer while following thoroughly the hypothetical advance, a distance corresponding to the value indicated converted in the unit agreeing on the scale of the map. The point of result will give, compared to the origin, the ray of an arc of circle passing by the required station.

Here the problem becomes complicated : we not have one, but two unknown successive points. Thus, for Tamnum , we will start from Blaye, and even a point even nearer, than we know to locate in Saint-Ciers-sur-Gironde, of the terminal of the village of Babinots.

Let us trace on map a first ray curvimetric of 18 kilometers, passing by Tamnum .

This stage, we are obliged to make an assumption : Novioregum would be located at the Gallo-Roman ruins of "Le Fâ" with Barzan , in CharenteMaritime. The air archaeological discoveries confirm the existence of a great Gallo-Roman agglomeration and a port (Dassié, 1975). Let us trace starting from Barzan a second ray curvimetric Novioregum / Tamnum, that is to say XII * 2,45 = 29,4 km.The intersection of the arcs of circles is done near the locality of Consac, in Charente Maritime, locality where was found a milliary column carrying titulature of Antonin (C.I.L. XII, 8899). It is there that we locate Tamnum , in Consac, provided the point of Barzan finds another validation.

In the publication of 1977 (Dassié, 1977), we proposed the localization of Tamnum with St Ciers-du-Taillon.There is no contradiction since the intersection of the circles is to 2 km between the two very close localities. But Consac is more remarkable by its milliary column and the termination of its toponym. Moreover, on the passage supposed of the way towards Novioregum, are two villages with the particularly revealing toponyms: " Les Grands Milliers " and "Les Petits Milliers" (from the french "borne millière") .

The localization of Novioregum to "Le Fâ de Barzan" must answer one second condition  : to be with XV leagues (2450m) from Saintes ( 36 km). Curvimetric measurement on the possible way, by Chermignac-Rétaud-Thaims-Cozes and Arces gives results 36 km approximatly. And the arc of circle falls on Barzan.

This second condition is met perfectly and the sequences of rays curvimetric confirm the localization of Novioregum with Barzan .

It is thus quite naturally that this name is now given to the city of more than three hundred hectares, distributed around "Le Fâ" and of the theatre of "La Garde", and whose new district of the " Les Mottes Gachin", in the commune of Arces (Charente Maritime), was discovered in 1997.