CIPA 2003 XIX 11 ' International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
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• the final image of the orthophoto is made up of small
portions so as to optimise the production process of large
orthophotos: it should be recalled that a colour orthophoto
of a map sheet in 1:2.000 scale (standard size) with
ground pixels of 20 cm (~ 300 dpi) is made up of about
105 Mbytes (about 6600 x 5500 pixels);
Figure 5. Window to choose the images of the block
Figure 6. Some user interface windows
• the orthoprojection procedure allows the extraction of the
available images in which each above mentioned portion
has been identified (see fig. 5): in this way, the loading
operations of the input images are limited, considering
that there are a maximum of 6 images of interest; •
• the layout of the orthophoto can be defined on the basis of
the standardised map-sheet format for the technical large
scale cartography: the operator chooses only the scale and
the considered sheet and then the software determines the
co-ordinates of the 4 vertices of the map. The pixels that
fall outside the sheet format are forced to be white in the
final orthophoto;
the software generates a georeferenced digital image that
can immediately be loaded and used in a GIS;
the user interface was completely rethought up, taking
advantage of the possibilities offered by Visual
FORTRAN language in a Windows environment. The
main window, two data input windows, the window
inherent to the cartographic format and the processing
stage can be seen in fig. 6.
Figure 7. Images extracted from aerial photos of Mole
Antonelliana (a) and the Gran Madre Church (b)
5. TRUE ORTHOPHOTO OF THE CITY OF TURIN
The Municipality of Turin decided to integrate its GIS with a
true orthophoto of the whole territory.
For this reason it ordered a colour photo flight at a scale of
about 1:5.000, which is also adequate to update its digital map
in scale 1:1000. The images were oriented using a bundle
block adjustment. The photos were later acquired using a photo
