Time-efficiency 
The experiment used for attribute accuracy 
evaluation was also used to evaluate time 
efficiency. The time needed for the orientation of 
each system was registered, and the time required 
for interpretation and digitizing of line features 
was expressed in meters/second. 
The times needed for orientations were as follovs: 
5 minutes for the IGN map prior to digitizing; 30 
minutes for the monoplotting system, including the 
orientation of the photograph and determination of 
the exterior orientation parameters; 3 hours for 
the orientation of the analytical plotter, 
including inner, relative and absolute orientation 
for two models as well as edge matching. 
Unfortunately, the recorded digitizing rates were 
not conclusive and further experiments are needed. 
CONCLUSIONS 
The obtained results indicate that interpretation 
by analytical stereoplotter is better than digital 
monoplotting, because of its stereo viewing and 
magnification. This was demonstrated by the rate 
of success with linear features in the attribute 
accuracy evaluation. 
The results of the positional accuracy test show 
that by relaxing the specification, data collected 
by monoplotting from scale 1:30,000 photographs 
are suitable for updating a  1:30,000 scale 
database with 0.5 mm accuracy at 80% confidence 
level. It should noted, however, that the digital 
monoplotting system cannot be used if the terrain 
relief has changed and the DTM is not updated. 
The use of analytical plotters is recommended when 
high precision is required and/or when extensive 
database revision projects are planned. Digital 
monoplotting can be particularly valuable for 
revision or primary data acquisition processes in 
certain application fields, such as forestry, 
geomorphology, etc., where results of 
photo-interpretation of natural resource data must 
be transformed to a reference coordinate system. 
REFERENCES 
1. “Aronoff, S. 1989. Geographic information 
systems: A management perspective. WDL 
Publications, Ottawa. 
2. Bouloucos, T. 1989. Applied statistics and 
quality control. Lectures notes ITC, Enschede. 
3. Caspary, W., Scheuring, R. 1992. Error-bands 
as measures of geometrical accuracy. In: Proc. 
EGIS, Munich. 
4. Chrisman, N.R. 1989. Modelling errors in 
overlaid categorical maps. Accuracy of spatial 
databases, edited by Goodchild, M and Gopal, 
Taylor and Francis, London. 
5. Chrisman, N.R., McGranaghan, M. 1990. Accuracy 
of spatial database. Unit 45, Technical Issues 
of GIS,NCGIA Core Curriculum, Univ. of 
California. 
6. Kunarak, R. 1992. Low cost feature extraction 
from aerial photographs. MSc thesis ITC, 
Enschede. 
7. Makarovit, B. 
Journal 1973-4. 
1973. Digital monoplotters. ITC 
498 
10. 
11. 
12. 
13. 
Makarovid, B. 1982. Database updating by 
digital monoplotting. ITC Journal 1982-4. 
McKenzie, M.L., Makarovic, B. 
plotter evaluation guide. 
paper, ISP Hamburg 
1980. Analytical 
Comm.II, -W.G 1 
Meijerink, M.J.A., Valenzuela, R.C., Stewart, 
A. 1988. The integrated land and watershed 
management information system. ITC Publication 
Number 7. 
Radwan, M.M., Makarovi¥&, B. 1980. Digital 
mono-plotting system, improvements and tests. 
ITC Journal 1980-3. 
Slama, CC. (editor) 1980. Manual of 
photogrammetry, 4th Edition, American Society 
of Photogrammetry. 
Tempfli, K. 
sampling: 
supported 
1986-2. 
1986 Composite/progressive 
A program package for computer 
collection of DTM data. ITC Journal