Olivier BARGE / Emmanuelle RÉGAGNON
(Archéorient, CNRS, Lyon, France)


  • Old city map production
  • propose a reliability map
  • Obtain an alive information system
  • Take advantage of display modes

Abstract: A major Islamic port city during the Middle Ages, the town of Qalhat was completely destroyed in the 15th century by an earthquake and invasion by the Portuguese. Only an immense field of ruins remains today. To draw up the urban plan, traditional archaeological methods proved unsuitable and too long to implement. The use of a differential GPS coupled with georeferenced aerial photos obtained with a kite quickly permitted reading of the information. This method of data acquisition was conceived to enable afterward the development of an information system. Thus, beyond exploratory consultation of the data and cartographic production, it provides an iterative approach, from use of the raw data to interpretation based on totally transparent criteria. The city plan obtained is no longer an unalterable result but a living document which may be subjected to criticism. Several interpretations – and thus several models – of the city may be proposed.

This approach is strengthened by the possibility of producing differing representations. Realization of a map of the city (for which different modes of representation may be presented) was the main objective of the work. 3D representations are also possible. More penetrative, these go beyond simple communication to the general public; although graphically simple, they are produced directly from the information system. They support the scientific arguments of which they are the reflection because they are based on data that can always be re-interpreted. These data are evaluated; examination of the quality of the field records enables proposition of a reliability map.

Keywords: Field acquisition, information system , reliability, 3D representation