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baseline of the East Coast beaches between Delware and South Carolina in the USA. The results indicated that an
accuracy of about 10cm in elevation data was achieved. Moreover, airborne laser scanning data have been used in the
determination of mean tree height in Norway for the purpose of forest planning. The results show that using such new
technology for this purpose gives results equal to or even better than those obtained by using the aerial photogrammetric
methods (Næsset, 1997).
The Department of Surveying of Rijkswaterstaat in Netherlands carried out a laser scanning process to get topographic
measurements in order to study the sources of errors in the system. The study indicated that errors may vary between
5cm and 200cm and mentioned that the main sources of errors are due to the uncertainty in determining the platform
positions and attitudes. The same study also, predicted that some errors might result from the laser range measurements.
However, the same study recommended that, by following adequate strategy in measuring to remove gross errors, would
lead to an improved accuracy (Huising and Pereira, 1998).
Kraus and Pfeiffer, (1998) record the use of the airborne laser scanning technique to provide data for digital terrain
modelling (DTM) of wooded areas. This data was shown to be of an accuracy equivalent to that obtained from wide-
angle images of scale 1:7000 using aerial photogrammetry methods to create digital terrain models in open areas. An
accuracy of 25cm was obtained in flat terrain. However, an accuracy of +10cm for the airborne laser DTMs is
achievable. Moreover, the airborne laser scanning system can be used in wooded areas even if the penetration rate is
only 25%.
Besides the previous applications, the airborne laser scanning technology has been used in hydrographic surveying
applications. A Scanning Hydrographic Operational Airborne LiDAR Survey (SHOALS) system has been developed as
a result of co-operation between the US army corps of engineers and the Canadian government in order to support the
US army corps operations and maintenance of federal harbours. The corps received SHOALS in March 1994 after field
testing in Florida. SHOALS started its final stage of development to become completely an operational airborne
hydrographic surveying system (Lillycrop et al., 1996).
4 CONCLUSIONS
LiDAR has been shown to be an accurate surface modelling tool. It is starting to be used in a wide range of
applications. Although there is some overlap of ability between LiDAR and photogrammetry these are different
measurement systems and therefore have the potential to be complementary to each other.
This project aims to investigate the relationship between LiDAR and digital photogrammetry both from a qualitative
assessment and a quantitative assessment. This will be achieved by establishing a test site, which has already been
established to the North East of Nottingham, UK. LiDAR and various scales (at present, 1:10000 and 1:25000 scale) of
aerial photography will be used to make comparisons of DSM and other extractable information in the assessment in
rural and urban areas. The assessment will not only look at the two methods independently but what can be achieved
through integration and fusion of the data. Latest results will be present in the poster presentation.
ACKNOWLEDGMENTS
The authors would like to acknowledge the support from the Egyptian Government.
REFERENCES
Ackermann F.. 1999. Airborne Laser Scanning — Present Status and Future Expectation. ISPRS Journal of
Photogrammetry & Remote Sensing 54 (1999) 64 — 67.
Csatho B. M.. Schenk T. A., Thomas R. H., Krabill W. B., 1996. Remote Sensing of Polar Regions Using Laser
Altimeter. International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part BI, Vienna 1996.
ERDAS IMGINE OrthoMAX, 1995. ERDAS IMAGINE Version 8.2, IMAGINE OrthoMAX User's Guide.
Manchester Computing (CHEST), UK and ERDAS Inc, Georgia, USA.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000. 49
