indicate the
0 perform the
igram and to
of the model.
Ise a modern
ed features.
vation Model
presentations
al File is also
ation System
indent on the
t include the
ustifiably be
m ownership
; often been
within the
ever if an
jined cost of
shipping,
overlooked.
tly simplified
e instrument
far less as
ve.
ons are no
. Personal
; PC may be
CPU speed,
1onitor is still
vill comprise
hic system,
y system for
| cost of a
5 payable for
system and
ees payable
is possible,
e economy
especially for a commercial installation. The time and
business opportunity wasted will often cost more than the
money saved.
8.0 CONCLUSIONS
An up-graded analog instrument, can produce a digital map file
indistinguishable from that produced by a modern analytical
instrument. Given proper instrument calibration, the accuracy of
some late model 1st-Order instruments can even be compared
favourably to an analytical instrument.
From a productivity point of view, an up-graded analog instrument
can be superior to an analytical instrument because of wider
choice of graphic and data structuring/checking software from
third-party sources. The limited automation provided by an
analytical instrument in model set-up is more than overcome by
superior compilation software systems.
Since the introduction of ISM DiAP (Digital image Analytical
Plotter) in the 1992 ISPRS Congress in Washington, a full up-
grade may no longer be advisable. Often, the total cost of
acquiring and up-grading an instrument is equal to that of a
complete DiAP system.
Additional benefit offered by DiAP such as real-time stereo
colour super-imposition of the digital compilation or digital
orthophoto option are not available nor technically feasible for
an analog instrument at all. In addition, the lack of spare parts
(some of them critical) and the maintenance cost of an analog
instrument must also be seriously considered.
REFERENCES
Szangolies, Klaus Von, 1966. Vorschlage zur einheitlichen
Testung und Bewertung von Stereoauswertegeráten,
Eingegangen: 1. 3. 1966 pp. 156-189
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