Determination of three-dimensional coordinates for surveys of cultural heritage building with digital photogrammetry

Abstract

Centro de Tecnologia e Geociências, Departamento de Engenharia Cartográfica The photogrammetry is the thechnology available most suitable in the cadastral survey of the built up cultural heritage. The work describes procedures for obtaining three-dimensional control points with precision compatible with the digital photogrammetric survey. The methodology associated with modern and traditional procedures, such as: use of Global Navigation Satellite System (GNSS) receivers to determine the three-dimensional bases; geometric leveling; transport of the coordinates from the base points to the locations near the features with the calculation adjusted by the least squares method to a method that determined the three-dimensional coordinates in function to the directors cosine to the angles measured. The method known as analytical spatial intersection was used to survey the control points of the church Our Lady of Deliverance, in the neighborhood of Varzea, in Recife-PE. The facade was photographed using a multi-engine Remotely Piloted Aircraft (RPA), of the quadricopter type. The images were processed using Bentley’s ContextCapture digital photogrammetry program. The control points presented a spatial accuracy of ±0.0046m in the result of the aerotriangulation. The digital photogrammetric process is completed with the photorealistic three-dimensional model of the facade that allows detailed documentation.