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Digital Surface Development of Large Cylindrical and Conical Structures With a Single‐Image Technique
Author(s) -
Theodoropoulou Iliana,
Petsa Elli,
Karras George E.
Publication year - 2001
Publication title -
the photogrammetric record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.638
H-Index - 51
eISSN - 1477-9730
pISSN - 0031-868X
DOI - 10.1111/0031-868x.00166
Subject(s) - raster graphics , conical surface , tower , raster scan , surface (topology) , scale (ratio) , computer graphics (images) , geology , optics , geography , geometry , computer science , mathematics , cartography , physics , archaeology
Normally, regular surfaces of architectural or archaeological interest can be accurately mapped with single‐image techniques. Whenever possible, such surfaces are developed digitally, or they are presented as suitable cartographic projections. This paper describes the raster development of two large towers, one conical and one cylindrical, with heights of 19m and 12 m, and diameters of approximately 10m and 8m, respectively. The towers, dating from circa 300 BC, are situated on Greek islands and are accessible only on foot. The first tower was imaged from its surrounding hills with several lenses, including powerful telephoto lenses. The other tower was recorded from up to 9m above ground level by means of a modified fishing rod carrying a lightweight 35mm camera. All the non‐metric photographs, taken at a negative scale of approximately 1:350 which allowed an overall accuracy of 3 cm to 4 cm to be achieved, were developed digitally and then mosaicked. The raster products are described and discussed.