1 2
T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 1 6
T W E N T Y T H I R D E D I T I O N
1
PROFESS IONAL SERV I CES
and incremental process which, after
much consideration, was felt to represent
the most effective use of resources.
In summary, the objectives of the exercise
were to:
• capture comprehensive survey imagery of
the castle internally and externally, and (at
little additional expenditure) the wider site
• provide corrected base-level survey data
for the castle and site in digital format
• digitally model the superstructure of
the castle internally and externally.
Once the digital modelling phase was
complete, the digital model would be used to:
• carry out a comprehensive moisture-
mapping exercise relating interior
and exterior thermal imagery
• act as a framework for representing/
overlaying the evidence from both past
and current analytical recording exercises
• permit the mapping of the history of
secondary (post-Lutyens) repairs
• form a resource base for other purposes
such as future recording or archaeological
works, and act as a basis for the cumulative
and/or more general mapping of the
evolutionary history of the castle
• provide information for
interpretative representation
• form the basis of a building information
model as a management tool for
the proposed works and for the
future management of the site.
The challenges of the site
The principal challenge for any works at
the castle is the inaccessibility of much
of its precipitous crag-top location. This
had hitherto precluded comprehensive
survey – accurate architectural survey
during major works in the mid-1990s had
only extended to the accessible areas of the
superstructure. The present project required
all-embracing survey coverage, which also
necessitated accurate modelling of the partly
vegetation-obscured rock-faces below the
castle’s walls in advance of stabilisation.
Another difficulty for more conventional
survey was the extreme irregularity of the
structure overall, its labyrinthine passages
and its curious internal geometry.
Data capture
The new survey involved data capture by
means of laser-scanning and high-resolution
digital photography, the latter taken both
manually and by means of a UAV (Figure 4).
Each technique was applied as appropriate so
that comprehensive coverage was achieved
of all areas. The efficiency of the exterior
coverage by the UAV also permitted entire
coverage of the topography of the field
and foreshore areas surrounding the site,
data which will be retained for ongoing
management of the site.
Creating the modelled imagery
The captured image data was registered
and combined to create a single model
(Figure 5). Point-cloud imagery was overlain
with the photographic to produce high-
resolution orthographic projections.
These were then digitised by hand to
overlay a stone-by-stone level of detail
and further corrected by hand on site.
Applications
Having achieved this level of dimensionally-
accurate base survey detail, the imagery
was then used as a basis for layering-on
various categories of qualitative information:
architectural data, condition-related
information, archaeological recording and
analytical observations.
The archaeological data from recording
works carried out by the author on the
north elevation during works in 1996 was
digitised and integrated onto the model as an
analytical layer. Analytical mapping included
the plotting of areas of repairs subsequent
to the early 20th century works of Sir Edwin
Lutyens, much of which involved the use of
inappropriate materials, particularly cement
and (internally) various proprietary products.
Thermal imagery is to be overlain on
the model both externally and internally to
attempt to map the routes of moisture ingress
into the superstructure. Drainage and water
run-off systems will be similarly plotted and
modelled in order to better understand the
complexities of the site.
The resulting model will also be a
powerful interpretative tool on which will be
plotted the analytical history of the castle, its
phases and evolution. When this information
is cross-correlated with the detailed historical
records for the site it will be possible to model
the structure at fixed points in its evolution
over its 500-year existence. This information
will be made accessible to the visiting public
on site as the work progresses, and will also be
accessible as a web-based resource.
Acknowledgements
The author would like to thank John and David
McCreadie, and David Connolly of CHC
Heritage for their assistance in the preparation
of this article, and the National Trust (North
Region) for permission to use material relating
to Lindisfarne Castle.
Further Information
Chartered Institute for Archaeologists
www.archaeologists.netHistoric England, ‘Surveying and
Recording Heritage’, 2015
(http://bc-url.com/recording-heritage)
TOM ADDYMAN
MA FSA FSA(Scot) MCIfA is
the founder of Addyman Archaeology and a
partner at Simpson and Brown Architects (see
www.simpsonandbrown.co.uk/archaeology).
Figure 6 The north elevation of Lindisfarne Castle: hand-recorded imagery from a survey in 1996 was digitised and merged with the digital survey carried out in 2015 to
show analytical information and phases of construction and repair.