iy data 
ystems 
nity is 
laims. 
cilities 
it, and 
ly will 
vident 
ntional 
s, and 
ftcopy 
t of a 
ystems 
testing 
ategy, 
und to 
pecific 
lation. 
sportation 
options 
softcopy 
mapping 
siven that 
hand is 
onform to 
taining to 
sues need 
ion. For 
ave been 
N and the 
Helava SOCET SET. Other systems are being 
considered for testing as well. 
This paper summarizes preliminary results of 
investigating the utility of using softcopy 
photogrammetric systems in place of selected 
WisDOT mapping operations. The evaluation 
concept, strategy, and results can be generalized 
for other agencies of similar production 
requirements. 
2. CONCEPT AND STRATEGY 
The evaluation project is designed to address: 
a) Functions and Operational Characteristics: 
These include software, such as input/output, 
orientation procedures, and extraction; hardware, 
such as mono and stereo viewing, floating mark 
operations and coordinate measurements, memory, 
and storage capacity; and other system related 
operational requirements, such as user interface. 
b) Accuracy: To determine if automated DTM 
extraction techniques do actually attain acceptable 
accuracies, the following tests have been devised 
for this purpose. 
- Comparing DTM generated by softcopy system 
automated correlation methods, against DTM 
generated manually by a WisDOT operator using 
conventional plotters. 
- Comparing DTM generated by softcopy system 
automated correlation methods, against DTM 
generated manually by a WisDOT operator using 
same softcopy system. 
The WisDOT mapping accuracy standards require 
that error must not exceed 0.3 inch for 100% of 
direct observations, and same for at least 90% of 
indirect observations. 
C) Speed: A substantial gain in time can be 
achieved if the accuracy attained by automated 
extraction methods are higher or at least 
comparable to that normally attained by an 
experienced photogrammetric operator. 
Another criterion is defined by operator-system 
interaction time required for a full end-to-end 
stereophotogrammetric process. Interaction time 
is observed in the softcopy systems and compared 
with existing WisDOT standards for a typical 
mapping operation. 
131 
3. EVALUATION RESULTS 
3.1 Data Management 
The images used in this project were scanned in 
22.5, 15, and 12.5 microns. The file sizes ranged 
340+, 235+, and 100+ megabytes. This range 
of data volumes requires significant storage 
capabilities. There are some options to deal with 
such extensive amount of data for production 
environment. These include options such as 
central data bank, local area network, etc. 
3.2 Eye Fatigue 
The Intergraph and Helava systems utilize two 
different technologies for stereo viewing. In both 
cases, however, the WisDOT operators 
commissioned to examine the systems on site, Le., 
UW Softcopy Photogrammetry Lab, expressed eye 
fatigue shortly after they used the systems. These 
operators were trained on, and routinely used, 
stereoscopic vision with optical components with 
continuous-tone hardcopy media. Optics of most 
conventional photogrammetric machines tend to be 
of high quality and craftsmanship, and hence very 
expensive. This is to ensure best visual quality, 
geometric accuracy, and above all, to enable the 
operator's eyes hours of focusing with minimal 
exhaustion. This can be generalized with 
operators of any conventional photogrammetric 
production facility. It is anticipated, however, that 
eye fatigue would be reduced as operators get used 
to the systems. 
3.3 Accuracy 
Comparing DTM generated manually by a DOT 
operator, using conventional plotter, against an 
automatically extracted DTM. 
Model 1: 
No. of DTM points Compared: 3046 
Average Error Calculated: 0.7067 ft. 
Standard Deviation: 1.063 
Model 2: 
Comparing DTM generated manually by a DOT 
operator, using Helava system, against two 
automatically extracted Comparing. Each was