Integration and Comparison of Close Range SfM methodologies for the analysis and the development of the historical city center of Bethlehem

The present paper illustrates a part of the methodological process of image-based acquisition developed for the documentation of the historical city center of Bethlehem, in the Middle East territory. The first mission of research activities, developed inside the international cooperation project "Management and control of urban growth for the development of heritage and improvement of life in the city of Bethlehem” (2018-2021), coordinated by University of Pavia in collaboration with the Municipality of Pavia and financed with the contribution of AICS (Italian Agency for Cooperation and Development), has been carried on through combined application of digital instruments, TLS and UAV, with the aim of developing "smart", low-cost and rapid execution procedures for the production of a reliable three-dimensional model of the historic city center. The paper shows the application of different photogrammetric survey campaigns in a portion of the historical town, acquisition problems and tests of morphometrical reliability of each output, in order to develop a general SfM database consisting of different definition levels of the photogrammetric models of historical city center.