14 
Original / 
photo 
_\ Orthophoto 
Fig. 5 
Configuration of off-line orthophoto printers 
The control unit may be a specially built one for the system , or a general purpose 
mini-computer with the interface. The input and output units may be optical-mechani 
cal or mechanical-electronic. The latter version can also be adapted to automatic 
drafting. 
The control computer may, in addition to accomplishing metric manipulation, process 
the pictorial information, e. g. invert density, filter noise, perform dodging, amplify 
or reduce contrast, etc. 
V. DIGITAL MONO-PLOTTING (D. M. P.) SYSTEMS 
Vi 
Another potential application of D. T. M. data in photogrammetry is the plotting of line 
maps from single photographs [ 13 ] . Though the concept of digital mono-plotting has 
not yet been implemented in practice,it seems worthwhile to draw attention to it. The 
approach appears particularly feasible for developed areas, which requires frequent 
re-mapping or map revision. It is also applicable to plotting from non-conventional 
photographs. An important practical advantage of this approach, with respect to the 
stereoplotting involved, is its simplicity of operation. 
A D. M. P. system encompasses three ba^ic modules (fig. 6): 
a digitising unit, a mini-computer, and a plotting co-ordinatograph. 
Thus, the system may employ the already existing equipment components.