Application of cartographic analysis to the characterization and measurement of archaeological coins

Abstract

Characterizing and measuring ancient coins is an important task for historians. Since the coin has a relief, it is possible to study the surface of the coin as if it were a terrain, creating a digital elevation model (DEM). A DEM is a digital representation of the bare topographic surface of the Earth and can be generated and managed using a Geographical Information System (GIS). In our proposal, the first step is to create a 3D model of the surface of the coin using photogrammetric techniques in a specific workflow. This workflow comprises the design of the data acquisition, orientation and scaling of the 3D model, followed by exportation as a point cloud. The acquired point cloud is then processed in a GIS to generate the DEM, using spatial interpolation techniques to derive a continuous raster-format surface. A range of typical cartographic analyses (visualisation, shading, measurements and profiling) is then performed on the DEM, which accurately represents the topographic surface of the coin. This approach enables the characterisation of the surface of the coin by highlighting distinctive features and providing both metric and visual information, greatly facilitating the examination of archaeological coins from different sets of tests.