Open Conference Systems, Kainua 2017

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Multi-temporal images and 3D dense models for archaeological site monitoring in Hierapolis of Phrygia (TK)
Giulia Sammartano, Antonia Spanò, Filiberto Chiabrando, Grazia Semeraro

Last modified: 2017-03-21


The archaeological areas are one of the fields in which the contribution of Geomatics techniques for Heritage documentation were employed since long time and are now getting popular. In recent times, TLS and RPAS systems become more and more interesting to be studied in excavations sites for monitoring purposes and solving large scale and comprehensive mapping matters both from terrestrial and aerial point of view.

The paper will focuses on these issue and on the great challenge of monitoring sites during time, integrating and conforming multiple data coming from previous metric survey projects or image data collected in the past for different purposes. The test-sites is the complex archaeological landscape of the ancient city of Hierapolis in Phrygia on which the MAIER – Italian Archaeological Mission of Hierapolis operates from the 60s of the 20th century and where Politecnico di Torino conducted several documentation survey campaigns. Some case studies in Hierapolis monumental areas about 3D modelling from image and range data represent nowadays an interesting attempt to answer these tasks. In particular, the presented cases involve many multi-temporal datasets that have been acquired by different university staffs in subsequent campaigns, in 1997, 2007, 2012, 2015, by employing various sensors following the evolution of the acquisition techniques offers by geomatics in the archaeological field surveys. 3D models are generated by terrestrial LiDAR and by terrestrial and aerial photogrammetric surveys; these dense models are intended to be compared and integrated with newer models generated by the UAV systems employed in last 2015 mission. In the Sacred Area of the Apollo Temple, two different datasets allow to perform investigation and comparisons before and after archaeological accommodation of the sepulchre of Apollo. The 3D model was created from images captured by a curbed balloon and further by another particular nadir point of view (a man harnessed and suspended from a crane collected photos using a Rollei semi-metric film camera); an UAV flight was performed lastly in 2015 by a EBee fix wing drone. On the other hand, in the massive complex of the Bath-Church the deeply damaged East wall was kept under observation during years until the securing intervention with a castle of tubes has been achieved: till that moment the pipes structure masks almost completely the wall, even during the last Lidar survey performed in 2012. The integration with previous images datasets collected before the securing intervention and used to generate a 3D model, want to overcome this limitation in a multi-temporal integration.

In such perspective, 3D data derived from digital acquisition and modelling constantly contribute to build a knowledge on the site and help to improve their communication. Furthermore the combination of digital models and direct observations of the excavations results can improve the enhancement of the dissemination aims.