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THE AP5 SOFTWARE 
System Concept 
The functional and operational characteristics of an Analytical Plotter 
are more and more conditioned by the. requirements of the environment 
within which the system is to operate. 
This environment, that typically but not exclusively is that of all the 
disciplines related to the knowledge of the territory and of its changes 
caused by the action of man and of nature, becomes more and more complex 
and demanding. 
  
Necessarily, the trend is towards a systemistic approach to the solution 
of the problems, through the process of more extensive automation and 
integration (informatic orientation) of the operational tools and methods. 
Ihe use and the extent of diffusion of the Analytical Plotter within 
this environment is a function of its capacity of integration at a system- 
istic level. 
From this point of view the most critical element is the software, 
certainly not in terms of quantity, but in terms of its practical useful- 
ness to the goal of integration. 
To this respect we must admit, after years of experience in the field, 
. that the traditional software implementation of the basic Analytical Plot- 
ter concept as the analytical emulation of analogue instruments and 
methods, has caused the freezing of the enormous potentiality of the 
concept into. procedure-oriented rather than purpose-oriented software 
structures. 
Ihe APS software structure was designed with the goal of overcoming the 
constraints of a conventional implementation and of giving an answer to 
the needs of integration with pre-existing or locally contingent systems 
and procedures. 
Structure Concept 
The basic fundament departs from the concept of PHOTOGRAMMETRIC WORK- 
STATION (PW). A PW represents the logical interface between the APPLI- 
CATION SOFTWARE and the PHYSICAL DEVICE (PD) consisting of the Analytical 
Plotter hardware. 
The software structure (see diagram at next page) develops itself around 
the central PD core along homogeneous functional layers. 
Ihe REAL-TIME (RT) layer implements the basic algorythms of the Analyt- 
ical Plotter, as well as several control and communication tasks. It is 
heavily device-oriented and it therefore represents a specific respons- 
ibility of the manufacturer. 
Ihe IOS layer (INPUT/OUTPUT SYSTEM) consists of a package of subroutines 
interfacing the application software to the real-time software. 
Ihe primitives of the IOS define the PW and actually make the hardware 
transparent to the outermost software layers. 
  
Making the IOS more and more available to the users who intend to program 
their own user-oriented applications (USER & SYSTEM INTEGRATION) is a 
policy of this Company. 
The outermost software layer shown in the diagram represents the STANDARD 
APPLICATION PROGRAMS, that is those programs that implement the manuf- 
acturer's standard photogrammetric procedures.