a methodology for documenting and modelling a large 
amount of monuments, using low-cost technology and 
introducing colored mosaics in this process. These 
objectives are supported by technological advances in 
the fields of digital image processing, digital 
photogrammetry, geographic information systems and 
multimedia. 
In this work we also discuss the problems we confront 
when developing the database concepts, acquisition and 
processing for a historical heritage site of more than 500 
monuments. 
2. BACKGROUND 
Laguna, the study area, is a small city in the south of 
Brazil, at the Atlantic shore, founded in 1676. In 1985 the 
city's commercial downtown colonial stile ensemble was 
recognized by the IPHAN as national heritage, therefore 
maintained since then under special Brazilian protection 
laws. 
The ensemble comprises circa 500 buildings whose 
utilization is basically residential or commercial, showing 
generally a reasonable state of conservation. A great 
progress has been registered under the leadership of the 
local IPHAN office. It provides, along with the city 
administration, qualification of the historical site so that it 
presents the demanded  infra-structure and urban 
equipment that allow the maintaince of the heritage and 
the development of its natural touristic potential. 
Therefore, local authorities look for alternatives to solve, 
in the short term, the most urgents problems of 
restoration. In the long term there are programs to 
improve the resident's understanding of the city by 
seminars and meetings, as well as by visual despollution 
of the commercial zone, by putting underground electricity 
cables, and by taxs reduction for those who keep their 
house in a good state of conservation. 
Two different governmental agencies run separated 
information databases, in order to manage historical and 
urban planning issues: 
a) Municipality of Laguna: its database comprises 
alphanumeric and geometric data that are still 
displayed and managed in analog format. It stores 
the data collected from field survey, which are: 
cadastral sheet; street map and existing public 
services for every parcel and; the geometric 
database comprising the blocks maps; 
b) IPHAN: its database is currently being converted to 
digital media and comprises architectonic 
characteristics and state of conservation of the 
buildings, as well as a database of the proprietors 
and photos taken by non-metric cameras. 
3. THE PROBLEM 
First of all, one may notice that a great difficulty comes 
from the fact that the databases only exist in the analog 
format. Therefore, they are less suited for urban planing, 
scenarios prediction or simulations. This difficults the use 
of these databases in analysis, simulations or any other 
644 
procedures that demand the management or 
manipulation of a large amount of data in a complex 
manner. 
The fact that these databases are maintained separately 
leads to redundancy and inconsistencies. A fine 
comparison of the databases reveals that since the 
buildings are surveyed twice (by the IPHAN and the 
Municipality of Laguna), similar informations are collected 
and stored also twice. When checking the data that 
describe an unit many inconsistencies can be identified 
due to different criteria adopted by the surveyor team or 
even because the data collection was not satisfactorily 
supervised. 
The insufficiency of the geographic basis was another 
problem. The lack of experience in cartography of 
IPHAN's staff and its limited resources made the Institute 
map the historical region by conventional means (manual 
tape measure) The results were not reliable 
geometrically despite the buildings' shape were correct. 
Any overlay analysis or even integration with other data 
sources (orthophotos, municipal cadaster, topographic 
maps) would be impossible due to its imprecision. 
These above mentioned problems diminish efficiency and 
reliability of the generated information; higher the costs of 
surveying and managing the database and; restrict the 
possible uses of the data (once the non-existence of a 
common index number for the buildings makes it not 
possible to cross the data in different databases). 
Furthermore, the higher costs turn the databank updating 
cycle longer, resulting in the maintaince of an out of date 
base 
4. THE SOLUTION 
The general methodology for a joint Information System is 
displayed in Fig. 1. It shows the results from a study of 
the current situation and the predicted state-of-the-art of 
software and hardware industries, conjointly with our low- 
cost documentation and recording goals and the possible 
uses of 2D and 3D information systems in a geotechnical 
cadaster as a modern planning tool. 
To make it easier to understand we will explain the 
construction of the 2D and 3D Information Systems for 
three different items: components of the RDBMS, 
components of the 2D-GIS and components of the 3D- 
GIS. 
4.1. Components of the RDBMS 
The first step in the development of the RDBMS was to 
define a primary key for each parcel, so that every unit of 
the database could be uniquely identified. This key was 
also designated to be the common access key, present in 
both IPHAN's and Municipalitys database, integrating 
and interchanging their data. The key included four 
different numbers representing: the district, sector, block, 
parcel and real state unit.