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3 - Town planning and territorial project maps. 
During the long debate that took place during the 
meeting in Milano that was quoted above, almost 
everybody agreed about a general Italian map at the 
scale 1:10 000; Solaini was the mouthpiece (1). A 
plan at such a scale is not symbolic anymore: it is 
possible to reproduce it in scale. 
With modem methods of analytic resection, the 
uncertainty is bordered upon 1-1,5 metres both for 
plan mesures and for quoted points (at least 
doubled for level curves). In fact, plotting with an 
analytic instrument with an internal accuracy of 5 
?m, and taking in account all the other factors, we 
can confine the m.s.e. point restitution in 0.1 mm 
for position, and about four on ten thousand for 
height: that implies the above quoted numbers. 
At the moment we lack data about digital 
photogrammetry applications: as known, we don't 
have optoelectronic metric cameras yet (on a 
plane), we normally work with scanners obtaining 
the digital images from the usual analogic ones, 
and from its calibration. 
We believe that the 1:10.000 plan is suitable to 
study the territorial planning; it is very well 
"readable"; and the hardcopy printout allows the 
vision for a complete province. 
The Varese's one is, for example can be completely 
seen from the town planners if fixed on a wall. But 
we have to remember that, with suitable 
enlargements on a computer screen, it is not 
difficult to design planning modification. 
We have to be careful, for this reason, that the 
projects follow suitable techniques and we have 
not to dirty the paper with various unuseful grids. 
Quoting once more the meeting in Milano, most of 
the audience agreed with the use of the 1:10:000 
scale, at that time edited for the future Italian 
Technical Plan (then replaced as known by CTR). 
Among them, one of the fathers of the Italian town 
planning, professor Cesare Chiodi, who taught for 
a long time in our Politecnico, stated:"Plans at 
1:25.000, owned by almost all European countries, 
are not sufficient to an exhaustive representation of 
the town planning elements..." and more "the 
1:10.000 scale has the value to be sufficiently 
detailed for this research and town planning project 
level, and, at the same time, and it makes possible a 
good vision of the subject..." (6). 
Talking about the project with large pen trace, we 
will quote again from Inghilleri at the meeting in 
Milano: "... I have to say that, as engineer, I'm 
upset with architects. I have seen many town 
planning traced by felt tip pens, where the pen 
thickness means 20, 30, 40 metres. 
I'm not against working with the pen, but I think 
that technical and economical controls are 
necessary. These controls need a well done and 
sufficient cartography". 
As far as PRGs are concerned what more? Another 
quote from Inghilleri: "...I knew,' for example, that 
the town planning law states the realisation of town 
planning on plans with scale 1: 10 000, and that 
building plans need instead plans with scale 1: 5 
000. So I asked town planners: 'What are those 
plans for?' Town planners generally were not able 
to answer. 
They said, 'The law states this and we fit'. 
We try to answer now, taking the place of the town 
planners, who worked thirty years ago and, 
according to our lamented colleague didn't know 
the answer. 
A PRG has to be drawn on a 1: 2000 scale. 
The actual plan inaccuracy is twenty or thirty 
centimetres in position and height, if it is, of 
course, numerical and well made. No contest can 
rise in the design on the ground of the lines and the 
area prescriptions contained in a general town 
planning, if the uncertainty is limited to these 
values. If the uncertainty increases instead to one 
meter and more, as in using 1: 5 000 scale, the 
quarrels, even from an attorney-like point of view, 
will spread. 
One could opt for the same plan and scale also for 
the PE, PPA and similarities, also for working on 
plans with the eventual dispossession decree for 
public utility or other similar process; the 
communes often ask the scale 1: 500 for these 
plans. We think, on the contrary, the scale 1:1000 
is enough, if it is numerical and correct. 
Technical present possibilities make this product 
accuracy around a centimetre or just a little more. 
Now, we go back to the topic of the "pen". 
Even if the delimitation of the various areas of the 
PRG are defined by reasonable thickness lines (but 
often they use lines from 8/10 to 1 millimetre, and 
at 1:2000 scale that means a ground stripe 1.6 to 2 
metres wide), it is long-time tradition to identify 
with some feature the same areas. 
To this aim they use the most different dot and line 
patterns, that strongly limit the map reading, we are 
talking of the paper maps, used by professionals. 
The same map that is used by the communal 
technicians to trace new roads and squares and to 
define construction lines. 
This map is not the original, but a vulgar 
reprographic copy rolled on a side and so stretched 
on the other, with evident affine deformation 
effects of its contents. 
How to pretend then a correspondence between 
such a manipulated plan and the real ground?