Bettina Petzold 
  
One system is using fibre optics to build a push-broom of laser measurements. The laser beam is deflected in the 
different fibres of the fibre optic, which is opened to a push-broom. This results in parallel profiles of laser points on the 
ground and a very high point density in the flight direction. 
4 AIMS OF THE PROJECT 
4.1 Background of the Project 
When starting the project, only a limited number of private companies were offering the data capture and the require 
post-processing, often using proprietary software developed by each company. As the laser scanning technology ai 
also some laser parameters, as wavelength and laser frequency, varies between different systems, the results are difficul 
to compare. There is so fare no standard concerning accuracy and reliability of data or recommendations for differen 
parameters such as maximum point distances for a specific application. The main task therefore was to get an overall 
view of the state-of-the-art concerning production and use of laser data. 
4.2 Initial aims of the Project 
The initial aim of phase I of the project was to investigate the user requirements of laser scanning data and derived 
products, such as DEMs and 3D city models. A questionnaire was to be set up, concerning the requirements of the 
users, but also the user definitions of the derived products. Users of laser scanning data were also to give information 
about their definitions and understanding of these products. The first results of the questionnaire where only presented 
shortly during two meetings. 
In phase Il a test area was established comprising both built-up areas, forests and engineering objects such as power 
lines and railroads. The area should be surveyed by as many suppliers as possible. Data should be made public ani 
tested for different applications by the members of the WG. 
5 RESULTS FROM PHASE I 
The main work in phase I has been the formulation of the questionnaire and the compilation of the answers. 
The questionnaire was to investigate the current user requirements for laser scanning data. People were asked to give 
some details concerning laser data, used for different purposes as DEM / DSM derivation in wooden and/or urban areas, 
orthophotos, interpretation, 3D city models and so on. At the same time state of the art in research and development 
should be brought out, concerning the surface data and the derivation of other products such as DEM or 3D city models, 
The questionnaire was sent to about 300 addresses in 32 different countries of Europe. Of these, 79 were answered, 
corresponding to a return ratio of about 27 %. This is considered as a good return rate, revealing a high interest in laser 
data. This is confirmed by the 40 organisations that are not using laser data yet, but who are very interested in doing so. 
There are in addition 21 organisations that are testing laser data, most of them (15) universities. A quarter of al 
organisations that answered the questionnaire already used laser data in production. The answers have been compiled in 
graphic form to make it easier to analyse. The most important results and the corresponding graphics are given here. 
There has been a good geographical distribution of both sent and returned questionnaires. Since the result has been 
dependent on addresses given to the WG, countries with WG-members are generally better represented than other 
countries. Even though as many as 49 % of the received questionnaires told that they did not use laser scanning, they 
still found it worth returning the form (see Figure 1). Most users and potential users are working at administrations 
whereas most universities entitle themselves testing data. 
  
720 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000. 
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