ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
Terrestrial laser scanning for heritage conservation:
the Cologne Cathedral documentation project
D. Pritchard a•, J. Sperner b, S. Hoepner b, R. Tenschert c
b
a
EGIS, Heriot Watt University, Edinburgh, Scotland – dpritch5@jhu.edu
Metropolitankapitel der Hohen Domkirche Köln, Dombauhütte, Köln 50667 Germany –
(joerg.sperner, sophie.hoepner) @dombau-koeln.de
c
Otto-Friedrich-Universität Bamberg, Germany - ruth.tenschert@uni-bamberg.de
Commission VI, WG VI/4
KEY WORDS: Terrestrial laser scanning, 3D, heritage conservation, Gothic architecture, Cologne Cathedral
ABSTRACT:
Contemporary terrestrial laser scanners and photogrammetric imaging systems are an invaluable tool in providing objectively precise,
as-built records of existing architectural, engineering and industrial sites. The comprehensive three-dimensional (3D) recording of
culturally important sites such as heritage buildings, monuments, and sites can serve a variety of invaluable purposes; the data can
assist in the conservation, management, and repair of a structure, as well as provide a visually engaging educational resource for both
the public and scholars. The acquired data acts as a form of digital preservation, a timeless virtual representation of the as-built structure.
The technical capability of these systems is particularly suited for the documentation of a richly articulated and detailed building such
as the high Gothic Cologne Cathedral.
The 3D documentation of the Cologne Cathedral UNESCO World Heritage Site is a multiphase project developed by Heriot-Watt
University, Edinburgh in partnership with the Fresenius University of Applied Sciences, Cologne, and the Metropolitankapitel der
Hohen Domkirche Köln Dombauhütte. The project has also received generous support from Zoller + Fröhlich (Z+F) and the City of
Cologne.
1. INTRODUCTION
This paper reflects on-going research in the applied use of
terrestrial laser scanning (TLS) systems at architectural,
heritage and urban sites to generate dimensionally verifiable
point data to support the development of 2D CAD, 3D BIM,
3D animation and rendered imagery. The objective of the
multi-phase project is to utilise TLS to precisely threedimensionally document and analyse the surface areas of the
interior, exterior, twin towers, and adjacent precinct of the
Cologne Cathedral UNESCO World Heritage Site. The large
and richly ornamented Cathedral posed significant logistic
challenges, one of the reasons why the building had yet to be
comprehensively scanned.
At the creation of this paper, the Cathedral project is a work in
progress, initially focusing on the data capture methodology.
Further analysis of the 3D data is intended for applied
conservation purposes as well as its use in the generation of
3D models for architectural interpretation and enhanced public
engagement.
The documentation and development process during the
Cologne project addressed similar challenges as experienced
during the Scottish Ten Project (Lee, 2010), specifically the
Mount Rushmore USA and Rani Ki Vav India projects, as well
as the more recent work at Durham Cathedral and St. Michaels
Mount, England (Davidson, 2015).
2. THE COLOGNE CATHEDRAL PROJECT
2.1 Historic Challenges
•
Described as an ‘exceptional work of human creative genius’
(UNESCO 1995), the Cologne Cathedral was granted
UNESCO World Heritage status in 1996. The iconic building
is of tremendous emotive value to the citizens of the Cologne
and the German nation; it is also considered one of the most
significant architectural structures of European Christianity.
The original design of the structure dates to 1164 and during a
brief period, from 1880 until 1890, it was recognised as the
tallest building in the world.
Throughout its long history, the Cathedral has endured
numerous challenges and threats. Neglect, war, vandalism,
urban growth, and environmental pollution have all had a
significant impact on the physical fabric and structure of the
building. A brief list includes the effects of the French
Revolution, when the building was occupied by French troops
and vandalized when used as a stable and prison. In 1811,
architect Baurath Georg Möller surveyed the building and
reported the walls of the choir had shifted, the wooden roof
structures were rotten, the vaults cracked and rain water had
penetrated the masonry joints (Jokilehto 1986).
The most destructive events were during World War Two.
According to the Dombauhütte Archive, by the end of the war,
“the building was seriously damaged by 14 major highexplosive bombs and over 70 firebombs, it was also hit by
artillery and various projectiles. Most of the vaults in the main
vessels of the nave and transept had collapsed, the organ and
most of the nineteenth-century windows were destroyed, and
there were countless instances of major and minor damage to
the entire structure. The pier of the north tower had received a
direct bomb hit, which posed a threat to the cathedral. The
damage was repaired during the war using bricks as opposed
to matching stone.” (A brief history of Cologne Cathedral,
Corresponding author.
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
213
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
Image 1: Perspective point cloud rendering of main entry into the Cologne Cathedral. A combination of 15 terrestrial laser scans at
varying heights with 360-degree HDR imagery.
2017). Despite the extensive repairs since the war, damage is
still evident throughout many areas of the building.
Unfortunately, WW2 has an enduring legacy. In May 2015,
20,000 residents of Cologne were evacuated from the centre
of the city when a 200-kilogram bomb was discovered near the
Rhine River during construction work.
Contemporary conservation challenges are less-catastrophic
but equally significant. They include the impact of adjacent
engineering works, regional seismic activity, acid rain / air
pollution accelerating stone surface decay, global warming,
and vandalism. An ongoing concern is the pressure from the
public and tourism; the Cathedral is an important pilgrimage
and tourist site, with over 6 million visitors per year - as many
visitors as at the Eiffel Tower in Paris. These numbers have a
profound architectural impact in terms of accommodation
(ticketing, security, engagement), humidity, dirt, surface wear,
and vandalism. As an important pilgrimage site, the carbon
emitted from the millions of votive candles being lit
throughout the year.
In terms of architectural context, in 2004 the Cathedral was
inscribed on the List of World Heritage in Danger because the
UNESCO Committee believed that the “visual integrity” of
the cathedral was endangered by proposed adjacent high-rise
developments within the city.
Based on this background, a comprehensive TLS
documentation of the Cologne Cathedral provided an objective
3D as-built record of the entire building, capturing its current
physical condition including any previous surface damage,
building settlement, and structural shifting. The data provides
an invaluable dataset for future condition monitoring,
conservation, and interpretation.
2.2 Project Requirements
Initiated as a research project with the Dombauhütte, the
starting point of the documentation work was to demonstrate
the effectiveness of contemporary TLS systems at a large
heritage site. Given the prominence of the building,
remarkably at the start of the project the Cathedral had never
been completely laser scanned. As confidence in the project
grew, the scope of the project was expanded to include the
documentation of the entire World Heritage Site precinct, the
building exterior (at various parapet levels), the roof areas and
two towers. The project also included the main spaces within
the building.
In discussion with the Dombauhütte, it was agreed that TLS
systems would provide dimensional point data in a sufficient
quality and resolution (Böhler 2003) for their conservation and
maintenance purposes. Further justification for TLS included;
- The cathedral has been damaged, repaired and modified
over the centuries and existing records may be inaccurate
or under-detailed;
- A High Gothic cathedral is exceptionally ornate and
difficult to document using traditional survey methods;
- Despite the Cathedral's relatively large size, due to the
numerous parapets and ledges that surround the building,
the distance between scanner and building surface is well
within range of phase-based system;
- As recognised by UNESCO, the building has profound
international significance and deserving of a
comprehensive detailed archival record.
During the initial planning stage of the project the location of
the scanners were based on the requirement to have the overall
architectural form of the cathedral captured, but importantly,
as much exterior and interior surface area coverage as
possible. As an archival dataset, the adjacent architectural
context such as the train station plaza and museum precinct
was also included. The TLS position points were based on
several factors such as ideal laser range, data resolution, data
overlap, areas of occlusion, and visual obstruction. Specific
challenges included the highly-articulated facade, the
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
214
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
Image 6: Plan view rendering of the combined interior and exterior point data of the Cologne Cathedral precinct.
numerous flying buttresses and spires, the various parapet
levels, and the height of the two towers.
2.3 Documentation Systems
The two scanning systems used in the project were the Zoller
+ Frohlich (Z+F) Imager 5010C and the Imager 5010X
terrestrial laser scanners. Both systems were ideal systems for
the Cathedral project due to their speed, range, data resolution,
unit weight and the integrated High Definition Range (HDR)
camera system.
The 5010C and 5010X are phase-based systems, utilising a
Class 1 infrared laser, which is invisible, and rated as harmless,
completely eye safe for both operator and public. A concern
when scanning with heavy tourist activity at a World Heritage
site. Relative to other contemporary scanning systems, the
5010C and 5010X have an exceptionally high and rapid data
acquisition rate of 1.06 million points per second while
maintaining a linearity error of more than 1mm (within 20m
from surface). The systems have an approximate range of 187
meters and generate 360-degree point data based on a local
coordinate system with intensity values.
On completion of the scanning sequence, the scanners initiate
a series of 42 individual images, these are then combined to
form a single 80-megapixel image. An important
consideration in the documentation process is that the exact
nodal point of the internal 5010C and 5010CX laser sensors
and the onboard camera CCD sensor are at the same position.
The result is that during the data post-processing, the imagery
sits precisely onto the point data, providing photorealistic scan
dataset. The automated data alignment avoids the tedious and
time-consuming process of manual photography with
hardware systems such as a panoramic head.
For most of the interior scanning a Z+F SmartLight was
attached to the 5010C to assist in the illumination of dark
surfaces. The 1000 lumen light is specifically designed for the
scanner’s onboard camera with a neutral colour temperature
with a maximum range of 10m. Although the 5010C has an
HDR camera and capable of balancing low and high light
situations, a supplementary lighting system provided higher
detailed colour imagery and helped compensate limited
lighting conditions. The additional light was particularly
useful when scanning the nine baroque ‘Triumph of the
Eucharist’ tapestries suspended along the nave.
2.4 Project Planning and Implementation
One of the more compelling features of a Gothic cathedral is
the explicit architectural order and continuity of structural
features. The positioning of the laser scanners during the
project was purposely based to work with this existing
architectural order. For example, the scanner located at the
centre of and interior bay between the columns, or at specific
points between the buttresses or spires. The rationale was that
these positions provided the best view for the scanner but
given size and complexity of the building it required numerous
scan set-up and at the same time resulted in considerable data
overlap. The Z+F scanners were usually set at 3mm @ 10m
point spacing with a high level of range noise reduction and
full HDR imagery.
At the start of the project, existing Cathedral 2D CAD
drawings were used to position the scan stations by drawing
50m circles to determine set-up location and range. Working
with the architectural order, the interior/exterior scans were
proposed - using short distance scanning, multiple scan setups, inverting the scanner, positioning the laser scanner on an
extension arm, and an extendable tripod.
The Cathedral has an existing network of brass control
markers located throughout the building. The initial scans
were set over the fixed points using the laser plummet and the
heights recorded to provide further dimensional control. By
using the control network, performing a subsequent partial or
comprehensive laser scanning (e.g. in 5 to 10 years),
incremental surface changes or movement can be identified.
Most the interior scanning was at ground level and along the
20m level triforium walkway. Additional scanning occurred
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
215
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
Image 2: Preliminary design sketch of the laser scanner extension rig.
Image 4: Extension arm, North Tower Cologne Cathedral.
Image 3: Extension rig at Durham Cathedral, prior to the Cologne
project.
Image 5: The remotely operated, inverted 5010C TLS at the Cologne
Cathedral.
along the interior walkways at the 27m level of the north and
south towers. In one situation, the 5010X was lowered through
the ceiling keystone between the two towers using an inverted
tripod (image 5). To connect the interior scan data with the
other interior and exterior datasets, additional scanning was
done at the main and south entries. Four additional direct
connections were made at the north and south triforium levels,
connecting the interior through the 20m loft and then to the
exterior.
Most of the interior scanning occurred during daylight hours,
despite the numerous parishioners and visitors within the
Cathedral, the interior laser scanning was thorough. Most of
the interior surface areas of the nave, aisle, crossing, transept,
choir and ambulatory were captured. The exterior scanning at
ground had similar issues with commuters and tourists
walking through the scanner’s beam, but given that the people
were mostly moving, the short distance between the scans, and
the number of scans, the issue of scan data occlusion was
reduced.
A significant challenge with acquired scan data was the
number people being captured by the scanners onboard
camera, especially at grade level. Without further image
processing, the wrong colour information could be mapped
onto the cathedral surfaces.
The exterior scanning at ground encircled the entire Cathedral,
with additional scans of adjacent buildings within the World
Heritage Sector such as the Roman-Germanic Museum and the
Dombauhütte Administration Building. Using the exterior
geometry of the Cathedral, the scanners were positioned along
the various parapet walkways and Crossing Tower.
The above-grade positioning of the scanner benefited from the
wide parapets and accessible ledges, increasing the ability to
acquire upper-level surface area, especially around the south,
east, and north elevations. The TLS position points were also
beneficial in that the angle of the laser was more direct to the
surface as opposed to oblique when scanning from the ground
(a significant issue when scanning such a large building).
Locating the scanner on grade and on the roofs of the adjacent
buildings assisted in documenting the facades of the towers.
Coverage of the two towers was supplemented by the
horizontal and inverted scanning at the 150m level.
As listed in Figure 1, at present there are 608 terrestrial scans,
all with associated HDR imagery.
At the start of the project, it was determined that the data
registration would be based on a software-based, cloud-tocloud system as opposed to the extensive use of survey targets.
Although the lack of targets could reduce the speed of point
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
216
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
Interior Scan Locations /
Number of Scans
Exterior Scan Locations /
Number of Scans
Grade Level
84
Grade
Level
68
20m
triforium
26
20m
Parapet
Walkway
94
27m
towers
5
27m
Clerestory
Walkway
77
45m
(inverted)
4
45m
Parapet
Walkway
88
45m
workshop/l
oft
37
Crossing
Tower
8
Bell /
Sculpture
Room
10
North
Tower
50
53m
catwalk
11
South
Tower
46
Figure 1: Location and number of terrestrial scan stations,
Cologne Cathedral.
cloud registration as well as affect the level of accuracy
(especially if a Total Station was used to record the target
positions), cloud-to-cloud was preferable as it enabled a
quicker site setup, avoided the problem of affixing targets onto
a large heritage structure, and having to address the problem
of people obscuring or remove targets. A multitude of survey
targets would also effect the visual quality of point data.
2.5 Extension Rig
As most TLS are a ‘line-of-sight’ systems, by securely
extending the scanner horizontally outward, for example over
an exterior parapet or from an upper-level gallery, the scanner
can provide greater surface coverage and less occlusion.
Having the ability to initiate both the high-resolution scanning
and HDR imagery without additional hardware is
exceptionally advantageous. The 5010C/5010X can be
extended out of reach of the operator via an extension arm and
then remotely operated to capture a complete scan and imagery
dataset.
This extension method was proven to be successful during a
previous project at Durham Cathedral. By utilising a custombuilt aluminium extension rig the scanner captured highresolution surface data of the upper tower stonework. The
position distance and angle of the scanner to the stone was
shorter than scanning from a lower parapet and it provided a
greater level of detail of the damaged stone and mortar. The
configuration provided a unique view of the Cathedral roofs
that were not seen by a typical tripod set-up, as well as
captured other horizontal surface areas that are susceptible to
direct weather and bird damage. In this situation, the 5010C
was extended outward in an inverted position using an 8m
cantilevered truss and then operated via WiFi.
The Durham extension rig system required two technicians to
assemble and operate. The system is made of commercialgrade theatre aluminum trussing components, with two outriggers for additional lateral stability. The assembled system is
freestanding but for extra security and rigidity, a counterbalance and security tether were used. The total length of
scanner arm is 3.0m, with the inverted scanner being able to
extend outwards by 2.0m. The system takes 20 minutes to
assemble and sits on a thick rubber pad to prevent any
scratching of the floor.
The location of the scanner provided unique surface coverage
of the central Durham Cathedral tower, specifically the upperlevel horizontal mortar joints and exterior surfaces that were
most prone to weather and bird damage, as well as the roofs
below. The rig system clearly captured the four main roofs of
the cathedral, significantly reducing occlusion, aiding in the
survey control, and specifically connecting the uppermost
tower data with lower roof and ground datasets.
In certain situations, an unmanned autonomous vehicle (UAV)
may be used to acquire exterior surface detail of a heritage site.
At Durham and Cologne, an extension system was considered
the better choice as the UAV would require shutting off wide
areas to the public and there was a concern that the UAV could
suffer a catastrophic failure and damage the building.
The Cologne tower documentation benefited from the
experienced Cathedral scaffolding team who hauled and
secured a metal truss within the inside the 150m maintenance
levels of the north and south towers. As indicated in Image 4,
the 5010C was connected to a special bolted tribrach and
custom-built metal angle. This was attached to a rigid pipe and
then extended through the tower openings. The scanner was
located 2.5m from the exterior surface of the tower and had an
unobstructed view of the building below. Like the Durham
project, the scanner was remotely operated in a vertical
position and then inverted. The scanner captured the opposing
tower, both sides of the Cathedral roof (aiding in data
registration) and the horizontal surfaces of the towers below
the 150m level.
2.6 Data Processing and Point Cloud Registration
Image 7: Z+F 5010C terrestrial laser scanner, 27m level, Cologne
Cathedral.
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
217
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
Image 8: Cross-section point cloud rendering through the Cathedral and precinct. Note the foundation tunnel at the base of the tower.
The onsite scanning at the Cathedral occurred over 4
campaigns during a 10-month period. As each stage was
completed, a copy of the data was transferred to a workstation
for image development and preliminary data registration. The
first stage of the process was to develop the associated colour
information using the Z+F LaserControl (v. 6.5) software. The
software was used to create the individual .PNG images and
then edited in Adobe Photoshop to address any image colour
balance, saturation, or artefact issues, if necessary.
For production purposes, the data was organised per interior
and exterior levels. Trial registrations were carried out using
Leica Cyclone (v. 9.1) point cloud processing software using
automatic and manual alignment. Due to the high number of
scans the registrations were successful, as were the
bridge/connection points between the interior and exterior
datasets. The obvious challenge was to remove all the people
and tourists from the grade level scan data. To avoid repetitive
clean-up obvious artefacts and point cloud noise were
removed in each scan via the Cyclone software.
2.7 Post-Registration Data Development
At present, large orthographic .TIFs and perspective
renderings have been generated within Cyclone. To represent
the highest quality output of the scan data, large tiled
orthographic renderings of St. Peters Portal (the entry to the
right of the main entry) were made.
Cross-sections through the exterior/interior Cathedral data
have proved to be highly effective in visually explaining the
spaces and structural systems within the building. Further
high-resolution orthographic imagery is planned for each
buttress.
A unique outcome of this project was that through connective
scanning, a measurable line was generated from the lowest
‘built’ level of the Cathedral all the way to the top of the two
towers. By registering the various scan datasets, a direct line
can be made from the start of the South tower foundation to
the upper most surface of the two towers (see image 8).
Individual sections of the registered dataset have been
exported from Leica Cyclone as ‘unified’ .E57 format files
into Autodesk ReCAP 360 (v. 3.1) for further data cleanup.
Although there is an optimisation and reduction of the original
data when importing into ReCAP, the ease of real-time
navigation for data quality review and client presentation
purposes has proven exceptionally beneficial. In addition, the
ReCAP .RCP file can be quickly brought into other Autodesk
applications such as AutoCad or Revit for further CAD
development.
The interdisciplinary research project “Mittelalterliche Portale
als Orte der Transformation” (University of Bamberg) funded
by the German Federal Ministry of Education and Research is
currently working with the dataset of the St. Peter’s Portal.
Based on the point clouds and the orthographic .TIFs precise
as-built CAD-plans are drawn using Autodesk AutoCAD with
Faro Pointsense Heritage. Like in previous parts of the project
using point clouds as a base for the elevations, cross sections
and floor plans on different levels helped tremendously to
optimise the research workflow in terms of time-efficiency.
In addition, the level of detail given by the dataset ensures
precise as-built plans, even concerning the laying pattern of
the ashlars. These as-built plans are prepared for a one-week
research campaign on-site and will be used for mappings
showing information regarding surface deterioration, repairs,
and replacement of stones, as well as for studies on the
architectural structure and deformation. Based on the 3D
information of the point cloud and detailed research on the site
even exploded assembly drawings can be realised. The
research results will contribute to a clearer understanding of
how this unique medieval portal was erected and modified
throughout the centuries.
The workflow of using orthographic images of the
photorealistic point clouds can be adapted by the Dombauhütte
Köln as a basis for site monitoring and for the planning of
stone replacements. By using photorealistic and reflectance
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
218
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
based images derived from the point cloud, the CAD results
can be optimised.
at the University of Glasgow and lecturer at the Krieger School
of Arts and Sciences, Johns Hopkins University.
2.8 Future Data Development
The Scottish Ten Project was developed at the Digital Design
Studio at the Glasgow School of Art, Glasgow Scotland, the
Durham Cathedral Project was commissioned by IIC
Technologies and the Mount St. Michaels Project was
commissioned by CyArk, Oakland USA.
Future sub-millimetre scanning and digital photogrammetry of
the entryway sculptures is proposed. This data will be able to
reference the master scan dataset. The high resolution submillimetre structured light scanning (0.2mm) will allow
studies on surface deterioration, manufacturing techniques and
a comparison between the original sculpture and the copy (see
Beraldin 2004; Pavlidis 2007; and Pieraccini 2001) .
Further data processing work is planned for the individual
Cathedral buttresses, specifically separating out each as an
individual object and then generate orthographic-TIFs and 2D
CAD. The meshing of the point data will use ThinkBox
Sequoia software to generate 3D surface models. The plan is
to provide a comparative dimensional study of each buttress.
A proposed use for the Cathedral scan and image data is to
develop a dimensionally accurate 3D CAD model that would
be used in the future planning of the World Heritage precinct.
The urban dataset would be used for architectural design
development, and specifically, being able to review the
relationship between the new architecture and existing context
and the Cathedral. TLS derived data has the advantage of
providing the necessary information to develop a 3D urban
model, therefore avoiding potentially troublesome intellectual
property issues by mixing data owned by other organisations.
(Pritchard 2007, Ceconello 2008).
3.
CONCLUSION
This paper highlights the extensive use of TLS at the Cologne
Cathedral UNESCO World Heritage Site to acquire a
comprehensive, photorealistic 3D point cloud dataset of the
interior and exterior of the building. The use of numerous
short-range, multi-level scanner positions and extension rig
scanning, proved to be an effective way to digitally document
such a large and complex heritage structure. The Cathedral’s
immense size, height, and excessive human traffic were
certainly challenging but the results of the project were
successful and exceeded the original requirements of the
Dombauhütte conservation team.
As a work in progress, further research will be carried out in
the use of the data for conservation and monitoring purposes,
initially with the St. Peter’s portal and the choir buttresses.
Longer term, the dataset will form the foundation for the
development of an accurate 3D educational and engagement
tool for better-informed urban design.
4. ACKNOWLEDGEMENTS
The authors would like to acknowledge the tremendous
contribution and efforts of Zoller + Fröhlich, in particular Dr.
Christoph Fröhlich, Christopher Held and Philipp Kresser, in
the development of this project. Additionally, to recognise the
initiative of Prof. Chris Wickenden and the great support from
the staff and students of Hochschule Fresenius Köln. We
would also like to show our gratitude to the technical staff at
the Cologne Cathedral.
Douglas Pritchard has since left Heriot Watt University and is
an Honorary Research Fellow at HATII, School of Humanities
5. REFERENCES
Abmayr T., Härtl F., Mettenleiter M., Heinz I., Hildebrand A.,
Neumann B., Fröhlich C. “Realistic 3D Reconstruction –
Combining Laserscan Data with RGB Colour Information”,
http://www.isprs.org/proceedings/XXXV/congress/comm5/p
apers/549.pdf
Balzani, M., Pellegrinelli, A., Perfetti, N., Uccelli, F., “A
terrestrial 3D laser scanner: Accuracy tests”, Proc. 18th Int.
Symp. CIPA 2001, pp. 445-453, 2001.
Beraldin, J.-A., Blais, F., Cournoyer, L., Godin, G., Rioux, M.,
Taylor, J., Active 3D sensing for heritage applications in
Magistrat der Stadt Wien, Referat Kultur- elles Erbe, and
Stattarcha ̈ologie Wien. In: [Enter the Past]: The E-Way into
the Four Dimensions of Cultural Heritage. BAR International
Series, 1227. Archaeopress, Oxford, pp. 340–343 (2004).
Böhler, W. & M. Bordas Vincent & A. Marbs :
Investigating Laser Scanner Accuracy. Proc. of the XIX. CIPA
Int. Symposium, Antalya, Turkey, Sep. 30 - Oct. 4, 2003.
International Archives for Photogrammetry and Remote
Sensing (IAPRS). Vol. XXXIV – 5/C15, pp. 696-701 (2003).
Bork, R., “The Geometry of Creation: Architectural Drawing
and the Dynamics of Gothic Design”, Rutledge, New York,
(2016).
Ceconello M., Paquet E., “Virtual Urban Design”, 5th
INTUITION International Conference, Turin Italy (2008).
Davidson, R., “Documentation at Saint Michael's Mount:
Bringing Saint Michael's Mount into the 21st Century”,
http://www.cyark.org/news/documentation-at-saint-michaelsmount Oakland USA, (2015).
Jokilehto, J., “Part Three: Development of Conservation
Theories, A History of Architectural Conservation” D. Phil
Thesis, University of York, (1986).
Kacyra, B., Pritchard, D., Mitchell, D., “The Applied Use of
Advanced Documentation Technologies in Heritage
Conservation”, ICOMOS Scientific Symposium – Malta,
(2009).
Koller, D., Frischer, B., & Humphreys, G., Research
challenges for digital archives of 3D cultural heritage models,
Journal on Computing and Cultural Heritage (JOCCH) Vol. 2
No. 3, December 2009, ACM New York, USA, Article No. 7,
(2009).
Koelner-dom.de “A brief history of Cologne Cathedral.”
20/04/17. https://www.koelner-dom.de/geschichte/a-briefhistory-of-cologne-cathedral/?L=1.
Lee, E., “Digitising the Legacy” American Surveyor, Vol. 7
No.7, (2010).
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
219
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-2/W2, 2017
26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada
Lerma, J.L., Navarro, S., Cabrelles, M. and Villaverde, V.,
2010. Terrestrial laser scanning and close range
photogrammetry for 3D archaeological documentation: the
Upper Palaeolithic Cave of Parpallo ́ as a case study. Journal
of Archaeological Science 37, pp. 499-507.
Mettenleiter, M.; Härtl, F.; Heinz, I.; Neumann, B.;
Hildebrand, A.; Abmayr, T.; Fröhlich, C. “3D Laser Scanning
for Engineering and Architectural Heritage”, Zoller + Fröhlich
(Z+F) GmbH, Simoniusstr. 22, D-88239 Wangen, Germany.
McGregor C, Mitchell D, Pritchard D, Rawlinson A, Wilson
L, "3D Documentation of Global Historic Sites: The `Scottish
Ten' Project and its Applications for Cultural Heritage" in
Proceedings of 3D-ARCH 2011 Conference, Trento, Italy.
The International Archives of the Photogrammetry, Remote
Sensing and Spatial Information Sciences, Vol. 38-5 (2011).
Pavlidis, G., Koutsoudis, A., Arnaoutologlou, F., Tsioukas,
V., Chamzas, C., Methods for 3D digitization of cultural
heritage. Journal of Cultural Heritage 8, 93–98 (2007).
Pritchard D., “Digital Documentation of the Built
Environment: Construction of the Virtual City of Glasgow”,
CUPUM 2007, Iguassu Falls, Brazil (2007).
UNESCO World Heritage List, Cologne Cathedral No. 292
rev. August 1995
http://whc.unesco.org/en/list/292/documents/%23ABevaluati
on
Zacharias, D., Cologne Cathedral versus Skyscrapers – World
Cultural Heritage Protection as Archetype of a Multilevel
System, Max Planck UNYB 10, (2006).
This contribution has been peer-reviewed. The double-blind peer-review was conducted on the basis of the full paper.
doi:10.5194/isprs-annals-IV-2-W2-213-2017 | © Authors 2017. CC BY 4.0 License.
220