twelve sheets called
Rettangoli
. The content is similar to the two previous cadastres but with less details and ornaments in
representation. While maps are more synthetic, the description of the parcels provided in the register is more detailed.
The fourth cadastre consists of a corpus of varied and complex documents not directly consultable. The date of realization has
been hypothesized on the basis of the represented city and assumed corresponding to 1940. The city is divided into 34
sheets
Fogli
in scale 1:1000 and the degree of detail of representation is similar to the
Catasto Postunitario.
Despite the cartographical corpus is comparable to the other cadastres
analysed here, the system of archiving and updating information about parcels is more complex. Data about owners and real
estate are not collected in a single volume, but distinct in different documents
Schedario delle Partite, Schedario dei possessori, Elenco degli immobili
, now available on microfilm.
3.2 HGIS structuring and implementation
These datasets were scanned at high resolution 400 dpi and georeferenced using the procedure described in Bruno et al.
2015. For acquiring the Ground Control Points GCP for map registration the official Topographic Regional Cartography
CTR – nominal scale of 1:5000, reference system EPSG
23032 was used and a procedure derived from image block orientation in photogrammetry and in particular in independent
model adjustment was adapted for the registration stage. For the registration, a very simple C software code was
developed, which integrates GCP and common points between the neighbouring plates, and a conformal transformation
Helmert 2D model was applied. After the georeferencing stage, the plates were mosaicked,
having thus a unique and homogenous image of the city. Since it represents a different product from the original one and would
not replace original maps, also radiometric corrections were applied to maps, to uniform as much as possible the general
image of the city. With respect to only the
Atlante Sardi
and
Catasto Borbonico
, each plate was digitized Bruno N., 2014 through the vector
draw of the polygonal features corresponding to buildings, unbuilt areas, parcels and blocks.
This process allowed the creation of a spatial database, in which every single element can be associated to thematic information
gathered from the cadastral registers that accompany the maps. Simultaneously with the map vectorization, the cadastral
registers were transcribed Bruno N., 2014. The aim of this phase was to produce a digital transcription as close as possible
to the original source, but, at the same time, standardized and tailored for their correct entry in the database.
As far as the database structure is concerned, despite the complexity and the heterogeneity of the data under
investigation, due to the coexistence of more historical periods so distant in time, a unique database with the same structure for
all the historical periods was adopted. In fact, despite the expense of the general compactness and consistency on
individual sources, a more homogeneous database of all historical periods would allow diachronic queries more easily
and the maintenance of an overall structure rather simple. With respect to the choice of the RDBMS Relational DataBase
Management System for the system, we opted for a platform based on PostegreSQL, with PostGIS extension for spatial data
management. The choice was made for several reasons: first of all, its open source nature allows containing costs connected to
operation and maintenance of the system. Moreover, the opportunity not to be bound to a commercial solution provides
greater flexibility, so it is much easier to expand the level of interoperability with different GIS platforms.
3.3 Results and data publication
