Thus, when the advanced user wants to implement
a new model, she/he has just to edit the files within
the dashed boxes; the two mentioned files (the ma-
jor task) and other 5 remaining files (minor details
like output formats that are not absolutely necessary
since ACX will make default decisions). Then she/he
has to program a FORTRAN subroutine for the ob-
servation equations and their derivatives according to
certain calling conventions; this subroutine is added
to the ACX object module library and a new exe-
cutable module is generated. The pure photogram-
metric or geodetic engineer or scientist needs to know
very few about the program and just nothing about
the discrete and I/O modules.
6 CURRENT STATUS AND FUTURE
DEVELOPMENTS OF THE GeoTeX
SYSTEM
GeoTeX is an operational photogrammetric/geodetic
point determination system. Besides research, it is
supporting production projects in geodesy and de-
velopment projects in photogrammetry; the SPOT
model is undergoing implementation in collaboration
with the authors' colleagues of the Remote Sensing
Group and with the team of the Lehrstuhi für Pho-
togrammetrie und Fernerkundung at the Technichal
University in Munich [9].
There are two missing pieces in the system. One
is the interface to the photogrammetric, geodetic, to-
pographic and other data bases which, with the ex-
ception of the topographic —DTM— data base, are
undergoing definition.
The other missing piece of software is a level 2 in-
terface (Section 5.2) which requires a GUI system in-
cluding a GS.
Last, with the new generation of digital photogram-
metric stereo workstations, à closer integration of the
point determination system and the measuring in-
struments is foreseen. The stereoscopic display ca-
pabilities and the new fast hardware might change
some working routines in the sense of easier network
analysis and, in many cases, almost real time adjust-
ments.
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