3d Modelling of Topographic Objects by Fusing 2d Maps and Lidar Data

In the past few years the number of applications that use 3D information of topographical objects increased rapidly. With the growing demand for 3D topographic data the need for automated 3D data acquisition also grows. Height information can be extracted from airborne or terrestrial acquisition methods, but can also be modelled as implicit semantic information. Adding height information to existing features is insufficient; additional features have to be acquired and existing features might get an extra dimension (surfaces can be converted to volumes, etc). The challenge is to produce semantical, geometrical and topological correct 3D topography. In this paper we describe the steps to acquire 3D topographic information. Special attention lies on the user requirements of 3D models. These requirements have been accomplished by information analysis at four major geo-information organizations in The Netherlands. The four cases describe the wishes and requirements for 3D data and modelling. The most important acquisition task is the modelling of 3D infrastructure and 3D building models. In this paper we will focus on the modelling of 3D infrastructure in general, and specially the reconstruction of hidden infrastructural object parts. The developed method will be demonstrated with a 3D reconstruction of the complex motorway interchange ‘Prins Claus Plein’ near The Hague, The Netherlands, with multiple infrastructural objects crossing each other at different height levels. Although the focus in this paper will lie on the modelling of 3D infrastructure, the presented 3D map includes the modelling of topographic features completely covering the terrain.