{"id":2166,"date":"2016-10-14T17:12:09","date_gmt":"2016-10-14T16:12:09","guid":{"rendered":"http:\/\/archaeovision.eu\/?p=2166"},"modified":"2016-10-18T02:57:58","modified_gmt":"2016-10-18T01:57:58","slug":"city-of-london-guildhall","status":"publish","type":"post","link":"https:\/\/archaeovision.eu\/en\/projects\/city-of-london-guildhall\/","title":{"rendered":"City of London Guildhall UAV Photogrammetry Survey"},"content":{"rendered":"

During the summer, Archaeovision took part in the UAV photogrammetry survey of the Grade I listed Guildhall building in the City of London. The purpose of the survey was to produce a condition survey report of the\u00a0ceremonial and administrative centre of the City of London and its Corporation.<\/p>\n

The construction of the Guildhall began in 1411 and was completed in 1440, and remains the only non-ecclesiastical stone building in the City to have survived through to the present day. The only modification of the exterior is on the south front with the introduction, in the Neo-Gothic style, of the Dance Porch in 1788 by George Dance. The building provides an important record of the 15th century architecture of London and a continual assessment of the building\u00a0is necessary to preserve this record further.<\/p>\n

When producing condition surveys, our usual approach is to use laser scanning as the method provides a high resolution point cloud from which we can extract CAD data. With the work completed at the Guildhall, access to the surrounding area was limited; laser scanning would not have been able to capture the roof data necessary within the model. As result, we worked in collaboration with the Helicopter Girls<\/a>, who are leading UK drone operators in filmed based high end professional UAV services, to produce a photogrammetry model of the building.<\/p>\n

To produce the necessary photogrammetry model\u00a0to work from, over 1000\u00a0images were captured using a\u00a0Freefly ALTA 6 with a Sony\u00a0a7R II (42.2mpx) camera for aerial photographs, in conjunction with over 800 images from ground positions using our Nikon D810 (36mpx). The benefit of using high resolution cameras enables the data produced to be of a high quality and it enabled less photographs to be taken. The pilot used in the recording process is one of two people who are allowed to fly within 10 metres of buildings in the UK, therefore enabling a greater capture process. Having the license to fly so close to buildings enables close up data to be included and is something that is unachievable with other drone based surveys. This, in collaboration with our expertise in 3D recording, provides a system that is better than the majority of UAV based survey companies, as we are able to understand the necessary recording processes in cultural heritage, as well using the most up-to-date survey equipment.<\/p>\n

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