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Geoinformatics-8-2008
article figure 5: the bassett monument at carn brea (1836) and a tor which formed part of an earlier neolithic tor enclosure. this shows the potential for scanning prehistoric ritual landscapes also. have been impractical to do, let alone to be repeated easily many times in order to monitor its continuous alteration. the cd and dvd these too will inevitably be replaced by something else. this has direct implications when it comes to the storage of any archaeological information saved in a digital format. projects like those run by ruth tringham and michael ashley (uc berkeley) at catalhoyuk and organizations like the archaeological data service (ads) have started to address this issue by utilising the constantly developing nature of the internet. the most interesting forum for scandata (sets of coordinated points created from scans) is the cyark foundation (cyark.org). butrint, albania hellenistic theatre firm geometry and wide open space presented through the hellenistic theatre at butrint, albania (figure 2), reflected the easy at which data can be captured from very few positions in this case just two. in terms of the way in which the laser scanner was constructed to interpret the world, this is largely due to the 360 to 270° window of rotation that is allowed by the particular type of laser scanner used for this job. carn brea, cornwall the juxtaposition between the weathered and irregular surfaces of the neolithic tor and the geometrically sound 1836 bassett monument (figure 5) visualises a fundamental difference between high definition documentation (hdd) and the recording of archaeological monuments with conventional or established survey tools like the total station. unlike the total station or 2d survey, hdd is not concerned with the capture of individual points. the main differentiation lies in the capture of entire surfaces in one traverse and the rapid acquisition of data in the field. the baptistery, butrint, albania between 1924 and 1926, a group of italian archaeologists funded by mussolini were sent to butrint to reaffirm a strong roman presence on the site. a direct consequence was the reinterpretation and supposition of this agenda on to the material record. the italian archaeologists placed a ring of columns in the centre of the monument in order to 'restore' it to a more roman look. this is demonstrated through the re-jigged baptistery as seen in figure 3. the italian columns were digitally exaggerated in digital space through modelling as seen in figure 4. there are several elements that need to be taken into consideration. this is especially the case when we refer back to such meta artefacts in the future. in 2005 the minister of culture in great britain addressed the value of laser scanning the heritage sector by seeing it as a means of recording and preserving sites that are under threat, as she put it no substitute for the real thing but an alternative. this paper builds upon this by suggesting whilst scanworlds are no substitute for the actual thing they can act as a very valuable information tool proving the information present or the technology is taken for granted. a standard of practice must be put in place that accommodates for the development of laser scanning in archaeology in the long term. with the rapid evolution of such young technology the impressive data sets already available can only get better. in many ways a methodology needs to be developed that has purpose in mind. what gets done with the information after acquisition is as important as how it is acquired. in the long term the recurring importance of addressing each scan job with purpose in mind should also incorporate how the scan data can be used in the immediate and long term, as well as by whom it could and will be used (think about how the modeller could use this data and data such as note and photos gathered in the field). adam p. spring, heritage3d project officer, adamspring@gmail.com, heritage3d.org caradoc peters, university of plymouth, truro college campus, rutcpeters@plymouth.ac.uk, www.plymouth.ac.uk/pages/dynamic.asp?page=staffde tails&id=rutcpeters andrew wetherelt, camborne school of mines, university of exeter, cornwall campus, a.wetherelt@ex.ac.uk, www.exeter.ac.uk/cornwall/academic_departments/cs m/staff/andrew-wetherelt/index.shtml websites: www.heritage3d.org www.epoch.eu www.cyark.org www.worldarchaeologicalcongress.org/site/home.php http://extranet.getty.edu/gci/recordim the authors would also like to thank jon mills, university of newcastle and paul bryan, head of metric survey, english heritage, meg conkey, ruth tringham, michael ashley, alex baer, john chenoweth and sara gonzalez at uc berkeley, rand epich at the getty conservation institute, , sharron p. schwartz, robert van der noort, jean taylor, ainsley cocks, arjun sharma, daniel hunt, as well as the cornwall and west devon mining landscapes world heritage site, cornwall heritage trust and the camborne school of mines trust. examples the following examples demonstrate the power of recording cultural heritage as 3d point clouds of spatial information. the data comes from fieldwork carried out using a mid-range laser scanner. gwithian, cornwall the gwithian project was conducted in july and august 2008. it included mid-range laser scanning of the archaeological landscape in west cornwall where parts of the 1949-1969 excavations by charles thomas took place, as well as ground penetrating radar sampling of specific areas. the laser scanned point cloud produced from the project was done at 10 cm resolution over a 150 metre range and consisted of 5 scanworlds (modelled areas created through scanning) which covered a 64 hectare site in one day. whereas airborne lidar data is concerned with capturing height from above, the ground-based laser system used allowed for a higher resolution digital terrain model to be generated that also allowed for the colour coding and enhancement of archaeological features within that landscape as seen from the elevation colour coding in figure 1. prior to the advent of mid-range laser scanning, any recording of the geomorphology of a landscape would conclusion in this article, we have tried to highlight the various factors that must be considered using a mid range laser scanner to record and preserve archaeological sites and artefacts as digital artefacts within their own right. the relationship between the physical world and the digital environments are not that straight forward and 54 december 2008
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