58 — 
THE NEW « NISTRI » PHOTOCARTOGRAPH 
by Ing. U. Nistri 
The author, referring to his Photocartograph, which was devised as far 
back as 1919, describes his new Photocartograph, mod. Aeronormal IV, 
which retains the main characteristics of former model Aeronormal III ( 1 930). 
As a matter of fact, the instrument is an automatic plotter with direct 
double optical projection, without any optical means interposed between 
the cameras and the floating mark, which is objective and real. 
The observation of the images is objective also; the identification of 
the contour lines takes place according to the known principle of the trans- 
latory parallax, by blinking. 
The relative and absolute orientation of the cameras takes place by the 
system devised by the Author, of the auxiliary screens displaceable in the 
model space. The angulation of the cameras takes place by means of the 
known suport, due to the author, which allows of their rotation around a 
fourth axis, the nadiral one. 
In the new plotter, instead of the mark, wihch remains fixed, the whole 
optical model moves, so that the operator can confortably collimate from 
a fixed position. The controls of the coordinatometer and coordinatograph are 
electro-magnetical, exploiting known devices due to the author. 
In the new photocartograph the transposition of the cameras has been 
foreseen to the effect of executing spatial aerial triangulation. 
Moreover the binocular stereoscopical vision was not overlooked, by 
maens of an optical device (excluding anaglyphs) for the parallactic measu 
rement instrad of the blinking. This device for the photocartograph had 
already been submitted for consideration since the Exhibition which tock 
place at the same time of the IV Congress (Paris 1934) but it never had a 
practical employment, because the blinking method was found by the various 
operators more comfortable, practical and precise. 
The author stresses peculiarly on, and proves the reasons of his prefe 
rence for the direct double optical projection, and with the proving data 
furnished by the controls made on the hundreds of thousand acres surveyed 
since 1924 till dats, for the most varioud scopes and scales (1/500 to 
1/10.000), by the industrial organisation which was created by him, he 
states that with Photocartograph a C factor equal to 7.800 referred to an 
average altimetric accuracy equal to 1/5 of the interval while drawing a 
contour line, and a drawing speed for that line or any other planimetric 
detail of about 5 1 /2 km. per hour (i.e. about 1 1 /2 meters a second) have 
been easily reached. The author recalls at last the communications made in 
the previous International Congresses of Photogrammetry (Paris 1934 and 
Rome 1938) by the Bodies which executed the suveys, using his photocar-