Abstract

The Candis (temples) of Java represent sophisticated ancient building heritage and are key features for Javanese people to identify with their own culture. Candis occupy a significant position in the cultural history of Southeast Asia and rank among the most outstanding examples of Buddhist and Hindu architecture. Well-known Candis such as Borobudur or Prambanan are also top-ranked tourist destinations. This ancient heritage is threatened by Indonesia’s geographical location within the Pacific Ring of Fire, a tectonic subduction zone prone to environmental catastrophes such as earthquakes, volcanic eruptions and the resulting tsunamis. Previous work presented a monitoring workflow for analysing variations in the geometry of these temples to gain an understanding of structural changes produced by seismic events. As part of that workflow, we proposed a combined laser scanning and UAV-supported image match point cloud model which can be compared to a photogrammetric data set in order to provide a quick, inexpensive, and easily accessible monitoring technique. While methodology has already proved useful, some aspects still need to be refined. Also, further understanding about the structural composition of the objects being examined and what changes of geometry can be expected within the analysis after earthquakes needs to be collected. An analysis is presented of changes that have happened within the structure over a period of several years and numerous seismic events to facilitate an understanding of geometric changes that can occur. Furthermore, this re-evaluation by laser scanning will be compared to a set of image-match models to investigate factors that have an impact on the reliability and accuracy of such models. Manuals drafted by the project team and introduced in previous work explain how to capture image data to be processed into photogrammetric models. Amendments and revisions will be made to these manuals based on new data and experiences collected during the ongoing Candi Sari case study presented in this paper.