Modification of the orthoprinter to permit a larger slit and faster 
scanning could concievably halve this time. 
The process of selective rectification can be considered a 
truly universal rectification system. If the analytical plotter 
can accommodate the original photography end there are no known 
types of cartographic photography which it cennot eccommodete, then 
a precise rectified copy can be prepared. This rectified copy can 
be in any other desired type of geometry. This means that for 
relatively flat or gently rolling terrain perhaps the tedious 
process of preparing an orthoprint can be eliminated by selectively 
rectifying an original exposure taken, let us say, with 150 mm 
focal length to a geometry with a 300 mm principal distance. In 
this manner parallactic displacement due to relief could be minimized 
to perhaps acceptable tolerances. 
In situations where orthophotos are desired, the process of 
producing the orthoprint requires the setting up of the stereomodel 
in the analytical plotter. Here then, after the orthoprint is pre- 
pared, the expenditure of a comparatively small amount of time will 
permit also the preparation of a completely rectified diapositive 
which when matched with its stereo mate in a simple plotter, will 
permit delineation of the contours and other data desired in addition 
to the orthoprint itself. Relative end absolute orientation will be 
practically eliminated in the stereoplotter, thereby saving consider- 
able time and skill on the part of the instrument operator.