2.1.3 UNIX 
UNIX is the only standard multiuser multitasking 
operating system that runs on different hardware 
platforms from PC's up to super computers. The 
UNIX workstation plays an important role in 
engineering applications. It delivers minicomputer 
performance to the desktop and is as easy to use as a 
PC. Any Software application, written under UNIX 
can run on any UNIX platform. 
PC based UNIX systems will be a fast growing 
segment of the UNIX market. AT&T licensers resell 
the generic 386 code adding different features to the 
system. UNIX operating software is available from 
Interactive Systems or Santa Cruz Operation (SCO) 
for example. 
From my point of view, it is out of question that a 
software development for photogrammetric 
applications under UNIX is worthwhile and will be 
an investment in the future. 
2.2 STANDARDS FOR DEVELOPING END 
USER PRODUCTS 
Software developing means writing the source code 
including the algorithms and calling of library 
functions for user interfaces, and graphic output or 
data base management facilites in a high level 
language like C or FORTRAN. The compiler outputs 
the object code. The linker has to organise the 
adresses of each different software module and to 
connect the called up libraries. 
Languages like FORTRAN are designed for 
mathematical-engineering problems where as C has 
more advantages for hardware access. But today, 
mixed language programming can combine the 
features of languages. Including an interface in the 
calling modules is necessary for correct access to 
variables of different types. 
Designing own application libraries guarantees a 
redundancy free code and is easy to handle for a 
programming team. Some discipline is necessary to 
cooperate with the complete group, but the costs of 
higher development quality will turn out to be a good 
investment. 
Graphic applications can be written device 
independent by using libraries compatible to the GKS 
or PHIGS standard. The software is thus easily 
portable to other hardware platforms. Using 
standards like this makes documentation of interfaces 
and calling procedures unnecessary. 
   
In 1987, IBM published a unique System Application 
Architecture (SAA). SAA consists of four 
componets: 
e Common User Access (CUA) for the end-user 
interface, 
o Common Programming Interface, 
»« Common Communications Support and 
oe Common Applications for connectivity and 
transportability of applications across the entire 
line of hardware and operating systems. 
This publication resulted in a unique end-user 
interface for all alphanumeric shells as well as 
graphic user interfaces. Everyone who is talking 
about SAA standard, probably has in mind the CUA. 
But a lot of toolboxes for high quality looking 
interfaces like OSF/Motif for UNIX platforms or 
Formation on the PC and UNIX are existing today. 
Using these toolboxes is the only chance to write 
high quality software with acceptable effort. 
3. DESIGN OF A CLOSE RANGE SOFTWARE 
PACKAGE 
3.1 THE PHOTOGRAMMETRIC DATA BASE 
Modern data base management programs allow 
access to the designed data base from different 
application programs by using an interface on the 
programmer's level. Therefore, it is possible to 
manage the complete data base with a data base 
management tool in the background. This results in a 
redundancy free data base with fast and secure 
access. Software development in a team will benefit 
from this standardisation. Today there is no 
consequent handling of this concept, but future 
developments have to take care of existing standards 
in order to reduce development time. 
In close-range applications, there are approximate 
values of photo positions worthwhile for preparing 
huge orientation jobs and some algorithms even 
request these values. The access to camera data is 
given by the camera number. According to this 
number, the values for fiducial marks or réseau 
crosses are stored. The photo number gives the 
relation to the image measurement. The point number 
here points to the coordinates in the data set for point 
coordinates. Special coding is referring to the image 
coordinate system. The bundle adjustment program 
needs the input of weighted additional observations 
and results in object coordinates and improved image 
coordinates including some statistics. Further 
processing of the image material gives graphic 
information. Compiling the internal graphic format 
results in standard data file formats for interchanging 
data with further processing programs (Fig. 1).