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Title
New perspectives to save cultural heritage
Author
Altan, M. Orhan

469
try triangle
Journal of
eight mod-
^stem. In:
roceedings,
-72. ISBN
n using cir-
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1077.
H. Rush-
:dings, An-
dison Wes-
W„ 2000.
0, 2000).
, K., 2002.
itation sys-
ision 2002
n, Graz.
and Gool,
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The Vir-
Inter-
72-1:1997.
s/vrml97.
t and com-
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sion 24(3),
Berns, C.,
est heroon
DIGITAL SURFACE MODELS FOR ARCHITECTURAL HERITAGE ANALYSIS. THE SURVEY OF THE
AQUEDUCT OF “LOS MILAGROS” IN MÉRIDA, SPAIN.
Fernández Martín JJ.; Martínez Rubio J; San José Alonso J
Valladolid University, Spain.
School of Architecture
Laboratory of Architectural Photogrammetry.
WG 6
KEY WORDS: Architecture, photogrammetric recording, digital surface modelling, visualization techniques,
monument surveying.
ABSTRACT:
The documentation of a site such as a Roman aqueduct offers an excellent opportunity for testing the application of
software resources and techniques which are usually applied on civil works and modern cartography. The linearity of
this monument allows a very structured and systematic information management. We present a graphic documentary
work which is part of a bigger project aimed at the consolidation, restoring and illumination of the aqueduct. This work
serves as a basis for all of the involved sub-studies regarding lithology, archaeological analysis, rock and fabrics tests,
and structural analysis. It also acts as the graphic support for thematic maps related to biological colonisation, vandalic
attacks (graffiti) and other pathologies, history of restorations, etc.
The basic support for the survey works was based on widely-experienced topographic and photogrammetric
techniques; mainly the use of robotic reflectorless total stations, analytic photogrammetric instruments (Leica SD2000
and Adam MPS2), digital systems,‘rectification etc. All of these techniques are all well-known among our community,
but in this particular case further processes that imply some innovation in the field of Heritage Recording have been
our contribution.
Triangular Irregular Networks (TINs) offer very interesting possibilities for deformation analysing, exact volume /
mass calculations, material loss evaluations, measuring degrees of metheorissation, real time sectioning, automated
slope field graphing, etc. The digital modelling of the building surfaces represents an important qualitative approach to
overcome the limitations of wiremeshed models, as those digital models present a true three-dimensional topology that
makes the interpretation of the stone limits truly objective.
Beyond the application of the above mentioned quantitative analysis, surface modelling offers new ways to get realistic
virtual renderings. Three dimensional views that reveal qualitative aspects, such as texture and the response to different
illumination ways, have been other goals of the obtained results.
1. INTRODUCTION
This paper aims at the description of a practical application of
some tools offered by computer graphics, which are specific of
the field of civil engineering in the context of the analysis of
architectonic heritage. Professionals working on the
preservation and documentation of heritage recordings very
often have to face the problem of the inefficiency of graphic
design programmes, when they try to present and manipulate
the documented objects. In quite a few occasions, something as
simple as achieving partial visualizations, without the presence
of any obstacle or occlusion, implies certain problems that
make it necessary to make use of strategies which are
desproportionally complex in relation to the problem itself ( big
fragmentation in partial files, complex structures of layers or
level with the only aim of differentiating orientations...). This
is even more reproachable when, sometimes, this difficulty
makes it necessary to do without some useful information, in
order to make the visualization more legible.
The problem of spatial superposition can only be satisfactorily
solved by the application of some graphic tools which are not
currently found in the most frequently used CAD programmes.
In any case, the person doing the drawings must keep in mind
that the line-strings he is drafting are, in fact, sides of objects.
That is to say, they will have to build topological structures.
However, as we all know, when doing restitution one tends to
create very complex drawings which look like wire tangles.
Figure 1. 3-D files of the Aqueduct.