history

Photo

The pioneers

The image-based or photogrammetric approach of recording heritage has a long tradition. Beside the French militarian cartographer Aimé Lausedat (1819-1907), the German architect Albrecht Meydenbauer (1834-1921) was one of the pioneers of photogrammetry. Not knowing each other, they developed almost simultaneously photogrammetric procedures. Meydenbauer's achievements for the world heritage cannot be underestimated. He and his team recorded important sites in Germany as well as elsewhere in Europe and the Mediterranean. This included important built heritage and archaeological sites such as Baalbek, Persepolis and Athens. Meydenbauer's work was very much supported by emperor Wilhelm II, but incomprehension prevails about it amongst other heritage professionals of his time, like Ferdinand von Quast (General Conservator for the Built Heritage in Prussia) and Otto Puchstein (excavator of Baalbek and co-founder of Pergamonmuseum). On the missing support and animosity, he gained from Puchstein whilst working in Baalbek, Meydenbauer commented in his memoires “Er war mir nicht grün – He was ill-disposed to me”.The large 40x40 cm glass negatives were archived in the Könglich Preußische Meßbildanstalt, the remaining parts(20,500 images) are today stored in a special collection of Brandenburgisches Landesamt für Denkmalpflege - Messbildarchiv. His vision was the establishment of a cultural heritage documentation centre for the important World Heritage was unrealisable and is still not achieved to date, though several natural and cultural disasters shown how important such an institution would be. After his retirement, his associates continued the work until 1920, but soon after Meydenbauer's legacy was destroyed, the glass negative damaged by retouching and the institute reduced to an organisation producing and delivering images for commercial sale for publications on art history and postcards (Albertz/Wiedemann 1987).

 

Later history

Though photogrammetry was still frequently used in the recording of the built historic environment and sometimes in the evaluation of aerial photography in archaeological surveys, it did not find its way into field archaeology. Such an example are the large-scale urban excavations carried out in Dorcester or those by Martin Biddle in the 1970s at Winchester, where some experience was gained (Fussell 1982 / Anderson 1982). Though many pros of the technology were recognised, it could not be consequently used. The expenses for the highly precise metric cameras, evaluation equipment and the qualified operators were to large in analogue photogrammetry. Further products derived from the images were available with a considerable time-delay, films needed to be developed, the positives manually orientated and evaluated. The finished product was not available on site within a timespan where a check of its contextual correctness by the archaeologists was still possible as the excavation proceeded further. Therefore, photogrammetry couldn't be used as a real alternative to the manually drawn record.

 

Recent developments

Due to advances in computer technology during the last two decades and thanks to the availability of suitable consumer cameras and low-cost software, terrestrial image-based recording has now become much easier to use for the non-professional in recent years. Special analytic hardware is no longer needed and the data can be processed promptly in the site office. Orthoimages are produced to order and can be used as basis for manual mapping interpretation directly in the field. Nevertheless, it still requires basic knowledge of procedures and constraints as well as a careful acquisition of images and survey control. However, a solid half-knowledge leads many critiques to raise some points against photogrammetry. They belief that it is too inaccurate, too time-consuming, too expensive, outdated and old-fashioned and that state of art is laser scanning which is more accurate and faster. But all these assumptions are wrong, both technologies have their place and it is very much depending on the object and the resources available which one to use.

 

Literature

Albertz, J. / A. Wiedemann 1987, Architekturphotogrammetrie gestern - heute - morgen. Wissenschaftliches Kolloquiium zum 75. Todestag des Begründers der Architekturphotogrammetrie Albrecht Meydenbauer in der Technischen Universität Berlin am 15. November 1996, Berlin.

Anderson, R.1982, Photogrammetry: The Pros and Cons for Archaeology. World Archaeology 14.2, Oct. 1982, 200-205.

Fussell, A. 1982, Terrestrial Photogrammetry in Archaeology. World Archaeology 14.2, Oct. 1982, 157-172.