The database (prototype was developed in Visual FoxPro 
5.0) consists of three main tables containing 
alphanumeric and geometric data, which comprises: 
e Architectural Characteristics / State of Conservation / 
Orthophotos: description of every relevant 
architectural element present in the building as well as 
its state of conservation (Figure 2). Moreover, it is 
possible to visualize an orthophoto of the main façade 
together with some metadata (scale of source data, 
date of the rectification, executor, graphic scale): 
e Property Cadaster: contains data maintained by the 
Municipality of Laguna describing the property in 
terms of name and address of the owner, measures, 
physical characteristics (soil, slope, etc); 
* Street Cadaster: basically contains information about 
every road in the city (public services that are offered 
for every block in the city) and it is used in conjunction 
with the Real State Cadaster as a base for taxation. 
Moreover it also contains also the plant of every 
block, which can be edited directly in à CAD (Figure 
3). 
4.2. 2D Geographic Information System 
The 2D-GIS is still under construction. Its configuration 
joins the RDBMS and the Cadastral Basemap, in order to 
make it possible to query, analyze and model the RDBMS 
through the this basemap. In this way the advantages of a 
GIS at a large scale (1:2 000) are added aiming the 
information production for the decision making on the 
urban planning process. Furthermore, using tools already 
available for internet publishing (Arc View Internet 
Explorer is, for instance, one of them) will give access to 
the 2D-GIS through the WWW, thus increasing the 
possibilities of potential use for the stored informations. 
  
Figure 3 — Block plant screen at the RDBMS 
4.3 Generation of the Virtual World 
The 3D dynamic model of the city's historical downtown 
environment offers an interface with the 2D-GIS 
described in 4.2. This makes it possible to select an 
object in the 2D system and to observe it in a 
reconstruction of the real world, where not only the 
monument itself is feasible to be viewed but also the 
environment that surrounds it. Besides this, the selection 
646 
of the object in the 3D scene and the visualization of its 
data in the 2D-GIS is possible. 
The image acquisition is carried out in an A/D hybrid 
system. The analog photos are taken by a Pentax PAMS 
645 camera and digitized by an image spatial resolution 
of 25.4 um (diapositive) in a Microtek 45t film scanner. 
These images are then processed by the Photomodeler 
3.0 software, where the spatial coordinates of the 3D 
model for every façade are computed. The resulting 
model is exported to a CAD for edition and returns to 
Photomodeler for the final production of the orthophotos 
and the 3D facade. The orthophotos are then stored in 
TIFF format to compose the RDBMS, while the 3D model 
already with its true UTM coordinates (necessary to 
design the different objects in a common coordinate 
System), is stored in VRML format. 
Currently, the 3D model comprises the following objects: 
a DTM (retrieved from the Cadastral Basemap), the 
Mayor's Office, some houses and a baseplan, which 
contains the city block division. For the visualization the 
Cosmo Player 2.0 has been selected, one of the freely 
available Internet Browser's plugins for VRML rendering. 
A viewpoint of the model is displayed in Figure 4. 
  
Figure 4. Viewpoint of the 3D model. 
5. RESULTS 
It is important to mention that this project is not yet 
finished. The solution that shall support the connection of 
all components in one single graphic user interface is still 
under development. However, some considerations can 
be made when looking back at the problems we already 
solved and the ones we still expect to encounter. 
The measurements made on the plotted models have 
shown good results in terms of precision and accuracy 
when compared to the control points surveyed using a 
total station. However, it is still necessary to statistically 
determine these reliability parameters for both orthophoto 
and 3D plot. 
The analysis and comparison between IPHAN's and 
Municipality's database proved the problems we pointed 
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