Three-Dimensional Analytical Model Obtained by Photogrammetry 
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We are all aware of the utility and ease of use of this product, and it allows us to develop restoration project plans more easily (figs. 
18, 19). However, with this system we can also obtain “non-conventional” sections which are impossible to obtain if we do not have 
a complete 3D model, superimposing building elements of different drawings to study their relation or projecting diagonal elements 
on the general structure of the building by a drawing parallel to its development (fig. 21). To study the shoring that we need to build 
on the diagonal prop of the northeast corner of the transept and study its relation with the equilateral arch (diagonal) that we are 
undertaking on it, we prepared an elevation-section in the diagonal plane (fig. 20). 
22. Sectional view of transept with analysis of structural lesions. 23. Sectional view of transept colored by historical construction 
periods. 24. Internal structure of the historical database, with four primary tables and 46 secondary tables. 
25. Types of stone used in the construction of the western doorway 
In addition to drawing the edge lines of the structure, we have also represented the contours of each one of the visible materials on 
the building surface in our 3D model. This job is in itself a valuable construction analysis (figs. 15, 16, 19). But moreover, this 
manner of mapping the building allows for the individualization and identification of each item and allows it to be assigned a 
different specific value, using sections or colors. For example, it does no good if we recognize 17 different lithologies in the 
Cathedral walls if we do not know which is the specific one of each existing bed-stone or rubblestone (fig. 25). Neither does it help if 
we define the pathologies of these materials if we can not establish their specific distribution in the elevations. This individualized 
representation of materials also allows the identification of the precise location of position and placement of monitoring equipment or 
the point of extraction of specific samples for laboratory tests. On these construction elevations it is also very easy to precisely 
document the development of existing flaws and prepare a map of structural lesions, (fig. 22). Lastly, this representation of the 
materials has allowed us to perform an archeological analysis of the Cathedral architecture, assigning a specific USM (wall 
stratification unit) to each type of material and thus know the historical period when it was included in the building (fig. 23). 
In conclusion, we can say that this tool, with all of its graphical power, is inefficient without an information storage system acquired 
through studies of the building. A qualitative study of the materials and their conservation status is not enough, rather we need their 
quantitative estimation through thematic plans (figs. 23, 25) The MIS Monument Information System to which we have referred in 
the second point, establishes a computer relation between the values and features acquired in studies (database) and some topological 
values defined by the graphic contour we have used to represent each one of the materials in the building (3D model). Using this 
relationship, a two-way interactive query system is established between the data and values obtained and the measurable topological 
relationship in the 3D model (figs. 23, 24, 25). This MIS Management Information System forms - through its content and 
configuration - a complete documentation system on a monument. Moreover, due to its open system, it allows the operation and use 
of project processes and their revision and update during the execution of work, making it an unsurpassable tool in the field of 
monument restoration.