EXPEDITIOUS PLANIMETRIC ADJUSTMENT OF 
SMALL BLOCKS IN LARGE-SCALE MAPPING 
by Mario Fondelli, Eng. D. 
Summary - The A. briefly mentions the various problems connected with large-scale 
mapping and describes an analytical process for the planimetrie adjustment of strips 
undergoing aero-triangulation. This procedure is based essentially on the transformation 
from the instrument system to the terrestrial topographic system, by interpolation, of 
the plane coordinates of the various points observed. Then going on to stress their 
main features, the A. speaks of the practical appliance of this method for the ap 
proximate planimetrie adjustment of small blocks of strips used for large-scale mapping. 
1. The need for specialised maps is becoming more and more 
urgent in the field of large scales, where the study and planning of 
large size engineering and reclamation works often causes the experts 
concerned to be faced with quite peculiar conditions. 
In the vast majority of cases the orographic representation provided 
by a technical map, drawn up for that special purpose, must appear 
much more descriptive than that of any normal map, and at the same 
time provide a greater number of accurate altimetric indications con 
cerning the part of land represented. 
The altimetric accuracy of a technical map of this type must 
consequently be very high [ 1 ]. Notwithstanding the noteworthy progress 
attained by aerophotogrammetric methods, in many instances this ac 
curacy can only be ensured by a suitable spirit leveling on the ground. 
It is obvious that such an altimetric accuracy does not correspond 
to a planimetrie accuracy of the same order on a graphic representation 
at a given scale of the spot elevations and of topographic details. For 
this reason the planimetrie position of these points and details can be 
obtained, quite simply, by means of analogical aerial triangulation, 
once the said points and details have been located on the photographs. 
In such a case the appliance of aerotriangulation presents some 
quite characteristic features. The fact that we have a great number of 
altimetrically known points available, uniformly distributed along the 
various aerial strips concerning the survey, can in fact bring about the