Historical mapping and geoarchaeological reconstruction of the Roman city of Caesaraugusta (Zaragoza, Spain)

Abstract

In this paper we provide a reconstruction of the topography and characteristics of the terrain of Caesar Augusta (the Roman name of the present-day city of Zaragoza). This reconstruction has been modelled using GIS and integrating the topographic map drawn by Casañal in 1880 –previous to the main urban transformations-with geomorphological, geoarchaeological and archaeological data. Caesar Augusta was founded by Romans near the Ebro River in the 1st century BC in the same place where there was a previous Iberian settlement (Salduie). The urban area occupied a quaternary fluvial terrace in the confluence of the rivers Ebro and Huerva. The terrace stands about 10 m above these rivers, with a varying height between 208-200 masl. The present-day urban topography has suffered many transformations throughout history; therefore, it is impossible to reconstruct the original morphology of the land where the Romans decided to build their town in the past. We have used ArcGIS Desktop 10.0 and its platforms ArcMap and ArcScene for managing and analysing the data. 3D models show many fine topographic features that in were overlooked previous maps. These models are complemented with information about the underground geologic nature, which is known through the observations made in several archaeological excavations. The model derived from Casañal´s map and complementary data is only valid for general reconstructions, but it has enhanced our knowledge of many elements of Caesar Augusta (topography of the Decumanus and Cardo maximus, sewage system, moats, wall, theatre, forum), making it possible to better understand the geomorphology and fluvial evolution of the city of Zaragoza.