- 10 - e 
orientation elements of the left-hand photograph of the 
next-following model are considered equal to those of 
the right-hand photograph of the preceding model, and 
the coordinates of connecting points are used for changing 
from the scale of the second model to thatoof the first 
one. If errors of aerial pictures are accounted for,then 
the accuracy of the network is raised,approximately, by 
20%. 
Block networks are plotted chiefly with the aid of. 
isolated bundles without plotting terrain models, combiu- 
ing the plotting with adjustment of the photogrammetric 
network. Corrections to measured coordinates of picture 
points are also taken into consideration, and the exteri- 
or orientation elements, as obtained during the flight, 
are taken in account as well. 
COMMISSION IV. e 
Photogrammetric map compilation. 
In the USSR, the following map series and the 
corresponding contour intervals are in use ; 
Contour interval (m) for maps of different types 
of terrain 
  
  
  
  
  
  
  
  
Type of m — mmm tm mn oe rt em mn 
tora 152 000 | 1:5 000 | 1:10 000 [1:25 000 [1:50 000 |1:100 000 
Flat-plane . 0.5 0.5(1.0) 1.0 2.5 10 20 
Plane rugged 
and accidental 
with prevailing 
angles of slope 
up to 6? 1 1(2) 2.5 (2.0) 5 10 20 
F oothills and 
highlands 2 5 5 5 10 20 
Alpine - - - 10 20 40