1516 
the arches, and more particularly the plaster 
decoration of the vaults and the “iwans,” ata 
very oblique angle in order to preclude gaps, 
but nevertheless obtain complete and accu- 
rate elevations, profiles, and cross-sections. 
Analytical plotting methods are also used; 
the advantages and limitations of these 
methods are well known. Research is being 
performed in Sweden and Denmark to 
simplify their use and to rapidly obtain a 
point-by-point survey. A drawing is then 
made by a architect. Stability checks are an 
important part of the application of analytical 
methods; an example is offered by the suc- 
cessive surveys made by the IGN on the 
facade and narthex of the Abbey Church of St. 
Denis, just outside Paris. 
Experiments and works done with analyti- 
cal plotters are increasing. The Historic Mon- 
uments Survey Section of Canada (R. Letellier) 
uses an AP/C plotter provided by the National 
Research Council and finds the method ex- 
tremely worthwhile. Atthe Turin Polytechnic 
Institute, the plotter used is the Digital 
Stereocartograph (DS). C. Sena thinks that 
this system renders it far easier to form and 
orient the model in difficult cases (e.g., the 
amphitheatre at Susa), and the obtaining of 
drawings or numerical data of different kinds 
directly from the plotter is a simple matter. 
The value of such devices in architectural 
photogrammetry is obvious. While it is true 
that, owing to their scarcity and cost, they as 
yet belong to the luxury category of photo- 
grammetry, there can be no doubt that in due 
course such drawback will disappear and 
they will come into general use, to the benefit 
of architectural photogrammetry as a whole. 
We mention also further experiments with 
aerial photographs taken at very low altitude. 
The IGN and the SFS in France and the Nara 
Institute in Japan have taken photography 
from a helicopter with the camera fitted onto a 
stabilized platform; in Bulgaria a 210 mm 
camera was used, in an AH-14 plane flying at 
a height of 120 m and at a speed of 130 kms 
per hour, to take photography at a scale of 
1:600; and the Swedish Historical Monu- 
ments Department and Uppsala University 
have mounted a Hasselblad MK-70 camera in 
a sports-model plane. The new Japanese 
stereometric camera NAB-150 has been sus- 
pended from a kite-balloon. 
Finally, we should mention the increase in 
the use of inverse photogrammetry for the 
visual representation of proposed new build- 
ings on photographed perspective views. 
FIELDS OF APPLICATION 
We should concentrate this subject on cer- 
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1975 
tain given fields of application whose de- 
velopment is particularly noticeable. 
Surveys made for the preservation of 
monuments in peril or as a prelude to the 
transfer of monuments to a new site form a 
very important category of application. The 
most famous examples are those of the Tem- 
ple of Borobudur (Indonesia) and of the 
whole group of monuments at Philae (Egypt), 
protected under UNESCO international 
programs and surveyed by the French IGN. 
Structural problems in monuments are a 
sector of photogrammetric applications 
which is expanding in size and now includes 
studies of several different kinds. First, there 
are the stability checks, already mentioned. 
Next come the studies concerned with 
equilibrium; an example is the detailed sur- 
vey of the foundations of the church at 
Deerhurst (8th and 11th centuries) by the 
Royal Commission on Historical Monuments 
(England), conducted in conjunction with ar- 
chaeological excavations. We will also in- 
clude the IGN survey of the Pantheon in 
Paris, which has clearly brought out the distor- 
tions produced in the lower portions during 
construction and compensated for during the 
building of the upper parts. The survey 
should also provide a means for calculating 
the thrust exerted by the immense dome on 
the four central piers of the building. We 
would mention, too, the work of the Warsaw 
Geodesy Institute, which has re-established 
the structura! features and shape of the 
Wladyslaw Tower and the clock-tower of the 
king's castle with the aid of old photographs. 
The determination of geometrical charac- 
teristics with as great a precision as possible 
is an application closely linked to the study of 
structures. It was assigned particular impor- 
tance in the work carried out jointly by the 
Turin Polytechnic Institute (G. Inghilieri and 
C. Sena) and the University Institute of Ar- 
chaeology (G. Gullini), whether in the case of 
the Greek monuments of Sicily (proportions 
and optical refinements); the Roman build- 
ings, in which by surveying many cross- 
sections photogrammetry can ascertain the 
all-important internal spatial distribution; or 
the ziggurats of Iraq. In this case, photo- 
grammetry provided the means of com- 
prehending the forms ofthe buildings, check- 
ing the unit of measure used by the original 
builders, and analyzing structural variations 
between one story and the next. 
In this matter, we should mention particu- 
larly the study of the true forms of the in- 
teriors of large domes. The works of the Of- 
ficine Galileo (W. Ferri) and the Engineering 
Faculty of Florence University (M. Fondelli)