1.3 LOW COST - PORTABLE 
The MPS is delivered in a small suitcase measuring 800 x 400 x 250 mm 
and will operate satisfactorily in any normal office environment. It 
will also operate in the field if necessary, although normal precautions 
should be taken regarding extremes of temperature and protection from 
dust eto. In general it will operate in the same environment as the 
host computer. 
The system has been designed to be operated and maintained by the user 
and diagnostic software is provided to assist in checking the MPS 
Stereoviewer. 
2.0 SOFTWARE FEATURES 
The software supplied with the MPS is written in a highly modular 
fashion. It uses menus wherever possible to allow easy use by untrained 
personnel. The system allows all job specifications and control 
information to be entered on the screen of the computer console. Each 
field to be entered has a prompt to indicate what the user should enter, 
and most fields have a sensible default value so that the user need not 
enter anything in those fields. 
The system uses a small number of files to store job information, but 
the number of files and quantity of digitised data that may be 
accumulated on any one or more jobs is limited only by the storage 
capacity of the host computer. It allows the user to define feature 
codes to facilitate the produetion of final plots on an X-Y plotter with 
or without the intervention of post processing graphics packages such as 
AUTOCAD and PALETTE. 
2.1 SOFTWARE PORTABILITY 
The host ‚computer software has been written for any 16 bit 
micro-conputer which uses the MSDOS operating system as well as the DEC 
LSI-11/PDP-11 range of minicomputers. The programs are all written in 
Fortran IV (ANSII 66) and can easily be transported to other types of 
computers using different operating systems. 
2.2 TRANSFORMS IN STEREOVIEWER 
The real time perspective transformations are carried out using a 
microprocessor within the stereoviewer itself. This approach eliminates 
the need for an expensive interface and a high rate of communication 
between the host computer and the stereoviewer. The stereoviewer has 
two microprocessors, one for the transformations (an 8088 with 0087 
floating point maths co-processor) and another for the stage drive 
motors control (Z50). 
During the orientation proces the host computer records the 
observations, calculates the model transformation parameters and sends 
these parameters to the stereoviewer. Thereafter the stereoviewer 
controls the model and sends ground coordinate values to the host 
computer which simply records them on a disk iile and controls output an 
XY plotter and graphics screen. 
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