Ы. XXXVIII, Part 7В 
In: Wagner W., Szekely. B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B 
97 
F points 
o a0 I m l 
ita. 
0.02 
0.01 
0.01 
0.00 
300 350 
oint height precision 
oints; color-coded by 
iion odtm ■ 
vlost of the beach area 
dth the distance from 
the edges of the drive 
i at some point worse 
nt density. The DTM 
; to the low point den 
ser point heights and 
JRE WORK 
: empirical laser point 
entical points and the 
:d my a mathematical 
ent. Both values are 
laser points is around 
almost no bias in the 
immended to analyze 
l the QC of identical 
uence of the scanning 
; show that height dif- 
lepend neither on the 
» verify the influence 
it quality it is recom- 
>ints across the drive- 
L 
>int height equaled to 
1 within the weighted 
ht precision of terrain 
main influencing fac- 
iensity of terrain laser 
• of observations (i.e. 
ion of the observation 
>n of grid point height 
rrain laser points and 
exceeded the theoretical height precision of the individual terrain 
laser points. Rijkswaterstaat required a 1 x 1 m DTM having a 
precision better then 10 cm. Thus, it was concluded that those 
requirements can be easily met employing laser LMMS. 
The adjustment method for the DTM quality estimation includes 
just the grid cells with more than 3 terrain laser points and gives 
strictly speaking the precision of the grid points. Using another 
method would allow to compute the precision for all grid cells 
and would result in a slightly higher coverage. To optimally 
profit from the available data it is recommended that this method 
is adaptive to both point density and surface relief. Besides, areas 
without any terrain laser points, resulting from the shadow-effect 
or surfaces covered with a water, must be separately analyzed, 
e.g. see (Kraus et al., 2004). On the other hand, to asses the abso 
lute positional and height accuracy of the DTM product, external 
reference data of higher accuracy should be used. 
A last recommendation for further projects, assessing sandy beach 
morphology, is to place laser scanners on a higher platform. The 
StreetMapper platform of 2 m above the ground resulted in quite 
some data gaps due to occlusions behind the pre-dunes. Based on 
the DTM visibility analysis, as given in (Li et al., 2005), for a par 
ticular area of interest the optimal height of the laser scanner(s) 
above the ground could be calculated. 
ACKNOWLEDGEMENTS 
The authors would like to thank the Dutch Ministry of Trans 
port, Public Works and Water Management, for kindly giving us 
the StreetMapper data set. Besides authors would like to thank 
Geodetic Institute of Slovenia for supporting this research. 
REFERENCES 
Alharthy, A., Bethel, J. and Mikhail, E., 2004. Analysis and accu 
racy assessment of airborne laser scanning system. In: IASPRS, 
Vol. XXXV-B2, Istanbul, Turkey, pp. 144-149. 
Barber, D. M., Mills, J. P. and Smith-Voysey, S., 2008. Geomet 
ric validation of a ground-based mobile laser scanning system. 
ISPRS Journal of Photogrammetry and Remote Sensing 63(1), 
pp. 128-141. 
Cox, C., 2009. Subject: Questions regarding the streetmapper 
system. Personal communication. 3D Laser Mapping Ltd. 
Ellum, C. and El-Sheimy, N., 2002. Land-based mobile map 
ping systems. Photogrammetric Engineering and Remote Sens 
ing 68(1), pp. 13-17; 28. 
Geomaat, 2010. URL http://cms.geomaat.pageflow.nl. Accessed 
June 2010. 
Giaccari, L., 2010. Fast к-nearest neighbors search. URL 
http://www.advancedmcode.org/gltree.html. Accessed February 
2010. 
Glennie, C. L., 2007. Rigorous 3d error analysis of kinematic 
scanning lidar systems. Journal of Applied Geodesy 1, pp. 147— 
15. 
Habib, A. F., Al-Durgham, M., Kersting, A. P. and Quackenbush, 
P, 2008. Error budget of lidar systems and quality control of 
the derived point cloud. In: IASPRS, Vol. XXXVII-B1, Beijing, 
pp.203 - 209. 
Huaxing, L., 2008. Advances in Digital Terrain Analysis. Lec 
ture Notes in Geoinformation and Cartography, Springer Berlin 
Heidelberg, chapter Modelling Terrain Complexity (Section 2), 
pp. 159-176. 
Karel, W. and Kraus, K., 2006. Quality parameters of digital 
terrain models. In: J. Hhle (ed.), EuroSDR seminar on Automated 
Quality Control of Digital Terrain Models. Aalborg, Denmark. 
Kraus, K., Briese, C., Attwenger, M. and Pfeifer, N., 2004. Qual 
ity measures for digital terrain models. In: IASPRS, Vol. XXXV- 
B2, Istanbul, Turkey. 
Kraus, K., Karel, W., Briese, C. and Mandlburger, G., 2006. Lo 
cal accuracy measures for digital terrain models. The Photogram 
metric Record 21(116), pp. 342-354. 
Kremer, J. and Hunter, G., 2007. Performance of the streetmapper 
mobile lidar mapping system in real world projects. In: Fritsch 
(ed.), Photogrammetric Week’07, Wichmann Verlag, Heodel- 
berd, pp. 215-225. 
Li, Z., Zhu, Q. and Gold, C., 2005. Digital terrain modeling: 
principles and methodology. New York: CRC Press. 
Lichti, D. D. and Gordon, S. J., 2004. Error propagation in di 
rectly georeferenced terrestrial laser scanner point clouds for cul 
tural heritage recording. In: FIG Working Week 2004. Athens, 
Greece, May 22-27, 2004. 
Lichti, D. D., Gordon, S. J. and Tipdecho, T., 2005. Error models 
and propagation in directly georeferenced terrestrial laser scanner 
networks. Journal of Surveying Engineering 131 (4), pp. 135 - 
142. 
Petrie, G., 2010. An introduction to the technology mobile map 
ping systems. GEOInformatics Magazine 13, pp. 32-43. 
Schaer, P, Skaloud, J., Landtwing, S. and Legat, K„ 2007. Accu 
racy estimation for laser point-cloud including scanning geome 
try 2007. In: 5th International Symposium on Mobile Mapping 
Technology (MMT2007), Padua, Italy. 
Schwarz, R., 2009. Subject: Questions about the accuracy and 
precision. Personal communication. RIEGL Laser Measurement 
Systems GmbH. 
Shan, J. and Toth, C. K. (eds), 2008. Topographic laser rang 
ing and scanning: principles and processing. Taylor & Francis 
Group. 
Soudarissanane, S., Lindenbergh, R., Menenti, M. and Teunissen, 
P, 2009. Incidence angle influence on the quality of terrestrial 
laser scanning points. In: ISPRS Workshop Laserscanning’09. 
Paris, France; September 1-2, 2009. 
StreetMapper, 2010. Mobile mapping system streetmapper. URL 
http://www.streetmapper.net. Accessed June 2010. 
Vosselman, G. and Maas, H.-G. (eds), 2010. Airborne and Ter 
restrial Laser Scanning. Whittles Publishing.