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g 2008 
A 3D MODEL OF CASTLE LANDENBERG (CH) FROM COMBINED 
PHOTOGRAMMETRIC PROCESSING OF TERRESTRIAL AND UAV-BASED IMAGES 
Hannes Püschel, Martin Sauerbier, Henri Eisenbeiss 
ETH Zurich (Swiss Federal Institute of Technology), Institute of Geodesy and Photogrammetry 
Wolfgang-Pauli-Str. 15, 8093 Zürich, Switzerland, 
phannes@ethz.ch, (martin.sauerbier, henri.eisenbeiss)@geod.baug.ethz.ch 
KEY WORDS: Architecture, Building, Calibration, Close Range, Modelling, UAV, Visualization 
ABSTRACT: 
In this paper we demonstrate the workflow of 3D modelling and photorealistic texture mapping based on close range imagery 
acquired with a mini-UAV (Unmanned Aerial Vehicle) and in terrestrial mode. For generation of a highly accurate 3D model, a 
combined photogrammetric processing of these images was required. The conducted workflow consists of the following steps: 
project planning, flight planning, terrestrial and aerial image acquisition, camera calibration, control point measurement using GNSS 
(Global Navigation Satellite System), measurement of control and tie points in the images using the photogrammetric close range 
processing software Photomodeler 6, modelling and texturing of the object and visualization of the finalized model. Finally we 
achieved an excellent high resolution textured 3D-Model of the castle Landenberg with combining terrestrial- and UAV- 
Photogrammetry. 
1. INTRODUCTION 
1.1 Castle Landenberg, Sarnen 
This paper is based on the result of a bachelor thesis at ETH 
Zurich. The aim was to achieve a digital, photorealistic textured 
3D model of the castle Landenberg combining aerial and 
terrestrial images. 
Samen is the capital of Obwalden in central Switzerland. The 
so called “Schiitzenhaus” is the town's landmark at an exposed 
position in the west of the village. The object is not only 
important for Samen, but also for the whole canton Obwalden, 
therefore the “Schiitzenhaus” is printed as the symbol of the 
canton in the Swiss passport (Figure 1). The “Schiitzenhaus” is 
a valuable relict of the medieval castle in Samen. Furthermore, 
the object was chosen because of the personal relation of one of 
the authors to Samen and to the object. The “Schiitzenhaus” is 
one of the two buildings which remain of the castle Landenberg. 
In the 13 th century the castle Landenberg was built by Rudolf of 
Habsburg and at that time, it was the biggest in central 
Switzerland until the battles for freedom in 1291, where most 
parts of the castle were destroyed. From 1646 to 1998 the 
“Schiitzenhaus” was the meeting place of the Landsgemeinde 
(provincial assembly), until the public assembly was abolished 
in Obwalden 1998. Recently the castle is used for cultural and 
social events. 
Due to the height of buildings it was not possible to accomplish 
a full stereo coverage of the whole building using only 
terrestrial images. UAV-based aerial images are a simple and 
fast way to achieve the needed stereo coverage. 
For the data processing the following workflow was set up: 
Planning and image acquisition, camera calibration with 
i Witness, image pre-processing, image orientation and 
modelling using PhotoModeler (PhotoModeler 6), texture 
mapping and rendering using Blender (3D content creation suite, 
Blender 2.45), compare Figure 2. 
Figure 1: Zoom-in of page 13 of the Swiss Passport showing the 
Castle Landenberg.