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CIPA 2005 XX International Symposium. 26 September - 01 October, 2005, Torino, Italy_ 
A traditional orhophoto was created on the other part of the park 
(zone 2) using commercial software. The two products were 
then put together, so the first 1:1000 scale orthophoto of the 
Racconigi Park was thus created. 
Figure 5. Zone 1 covered by a True Orthophoto 
3. THE GIS 
The so far described operations made it possible to obtain a 
reliable geometric GIS base. A complete vision of the Park can 
be achieved with this tool, which offers the chance of 
overlaying different levels of information. The raw vector data 
obtained from terrestrial and photogrammetric surveys were 
edited (area reconstruction) and linked to the available 
information, for example, the sketches of the network vertices. 
The GIS environment was also supplied with products that are 
able to integrate the Park and its historical evolution 
description: the orthophoto, and the DEM. 
Figure 6. The TIN of the Park built in the GIS environment 
3.1 The Georeferencing of the Historical 1839 map 
The GIS environment was a useful aid in the historical research. 
In the hydraulic replanning of the park the Safeguard Office 
decided to reconstruct the historic situation represented in a 
1839 map as faithfully as possible. Using a rational function 
deformation model, the different measurement units and the 
deformation of the map were considered according to the age 
and the digitalization process. The map was georeferenced by 
selecting homologous points on both cartographic supports, 
making the residual errors on the point less than 3.5 m; the main 
difficulty was to find elements stable in time. Most of the 
chosen points were fences and building edges and the main road 
intersection. 
3.2 The hydraulic replanning 
The hydraulic simulation was carried out by a specialist team at 
the Politecnico di Torino. The GIS environment was used to 
derive the geometric model of the hydraulic network from the 
survey supports. The canal edges were derived from the 
overlapping of the actual geometries on the georeferenced 
historic map in the GIS environment. It was attempted to 
change the actual situation as little as possible; when in doubt, 
e.g. for the width of the northern waterway that had to be 
chosen, the GIS potentiality was applied to historical document 
data. The archive research work in fact produced work reports 
about the creation of some canals: in particular the length, 
width, and depth of each part of the last expansion works. It was 
therefore possible to reconstruct the geometry of these canals 
from the document data: using the present northern waterway 
centre line information and the excavation data, the width data 
were placed on the actual map. 
X 
Figure 7. Matching of the photogrammetric vector layers on the 
georeferenced historical map 
Y Map 
Residual X j 
58817.188468 
4.34625 
58527 498421 
3.64519 
58665,764352 
2.72271 
59340.550007 
0.81995 
59316.226625 
2.19777 
50114.563865 
2.56592 
50113.366758 
1.98242 
60134.016864 
7,13063 
58240.491866 
333769 
58389.232439 
3 58442 
58629 551846 
5.11801 
58814.030261 
0.69224 
59168.250281 
1.68408 
59264.916723 
1.25115 
58918.054786 
318180 v 
. . 
> 
a! RMS Eira {3.44287 
Figure 8. Map of the homologous points used in the 
georeferencing, and the RMS error. 
A good matching was observed between the present day 
geometric information about the length of the northern 
waterway and the archived excavation documents. This 
interpretation work led to the design of today’s restoration 
works done in that part of the park. 
3.3 The evaluation of the volume that has to be moved 
The GIS environment was also used to evaluate the volume of 
earth that has to be moved in the restoration works. The