Length surveying of the Ming Great Wall based on image interpretation and stereo mapping

Lack of information is one of the barriers for protecting the Ming Great Wall (MGW). This paper presents a method to measure MGW based on image interpretation and stereo mapping from aerial photographs. Firstly, we introduce a method to identify MGW using image interpretation based on sample data and document, from which features of the MGW were extracted. Secondly, a framework for building stereo model using multi-source image is proposed. Finally, we describe the length surveying for MWG based on stereo mapping and the construct of precision evaluation model, which can be used to evaluate the error of a three dimensional line based on a series of point errors. As a result, the total surface length of MWG is estimated as 8851.79 km with the error of ±312.95 m.