Ž .
ISPRS Journal of Photogrammetry Remote Sensing 54 1999 244–253
Suitability of laser data for DTM generation: a case study in the context of road planning and design
L.M. Gomes Pereira
a,
, L.L.F. Janssen
b
a
Ministry of Transport, Public Works and Water Management Rijkswaterstaat, SurÕey Department, PO Box 5023, 2600 GA Delft, Netherlands
b
International Institute for Aerospace SurÕey and Earth Sciences ITC , PO Box 6, 7500 AA Enschede, Netherlands
Abstract
Laser range data acquired from a helicopter are evaluated in terms of the information that can be derived from them and the accuracy. The objective is to study the suitability of laser data to generate a DSM for road planning and design in The
Netherlands. The conclusion is that high-density laser measurements allow the reconstruction of the terrain relief with the required accuracy. Nonetheless, they do not allow the extraction of all the information required, particularly semantic
information. Thus, the combination of laser data with existing information is a prerequisite. This process of combining laser data with existing geographic information is not trivial. The rate of success depends much on the quality of the individual
datasets and the method used to combine them. This problem appears in a much broader context, that of spatial data fusion, and should be the object of future research. q 1999 Elsevier Science B.V. All rights reserved.
Keywords: laser scanning; DTM; DSM; road planning and design; accuracy
1. Introduction
Rijkswaterstaat is involved in the planning, de- sign, construction and maintenance of the highways
in The Netherlands. Presently, Rijkswaterstaat main- tains approximately 3000 km of highways, having at
a minimum 4 lanes.
Because of the importance of the road network for further economic development, new highways are
being proposed and their impact, especially on the environment, needs to be evaluated. If the planned
Corresponding author. Escola Superior de Tecnologia e Gestao
˜ ´
´
de Agueda, Apartado 473, Zona Industrial-Alagoa, 3751 Agueda Codex, Portugal. Fax: q351-34-603838; E-mail: luisaestga.ua.pt
road has to be changed, alternative routes have to be planned rapidly. Thus, the method to acquire the new
information has to be fast. At present, road planning and design are carried out with the help of a DSM
generated by photogrammetric means. Because pho- togrammetry is a time consuming technique, infor-
mation is acquired over a much wider area than that needed to plan the initial road.
Laser scanning could fulfill the desire for faster methods. In this article, we investigate the suitability
of laser data to generate a DSM for road planning and design in The Netherlands.
Over the past years, Rijkswaterstaat has been experimenting on using laser scanning data to map
Ž the coastal regions of The Netherlands Huising et
al., 1996; Huising and Vaessen, 1997; Vaessen et al.,
0924-2716r99r - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž
. PII: S 0 9 2 4 - 2 7 1 6 9 9 0 0 0 1 8 - 0
. 1998 , and to produce a DTM of the complete
country in a grid format of 1 point per 16 m
2
ŽMinistry of Transport, Public Works and Water .
Management, 1997 . Obviously, these types of appli- cations are less demanding than that of producing
information for road planning and design. Although all applications require filtering of both blunders and
Ž undesired objects Fritsch and Kilian, 1994; Pfeifer
. et al., 1998 , the extraction of information from laser
measurements for the purpose of road planning and design requires more sophisticated procedures to re-
Ž cover and identify the objects on the terrain Weidner,
. 1996; Haala and Brenner, 1997 .
In the following sections, we will first present briefly the current practice of DSM production for
road planning and design at Rijkswaterstaat. In addi- tion, we will determine which type of information,
both semantic and geometric, can be extracted from high-density laser measurements. The planimetric and
altimetric accuracies of the laser data are also as- sessed by using reference measurements. The article
finishes with some conclusions and recommenda- tions.
2. Current practice of DSM production for road planning and design at Rijkswaterstaat
