Virtualizing Boathouses in Dwejra, Malta for Access through WebGIS Applications (Abstract)

Transcription

1 Virtualizing Boathouses in Dwejra, Malta for Access through WebGIS Applications (Abstract) Daniel LANGENHAUN, Erich BUHMANN, Matthias PIETSCH, Santosh CHOUGULE and Philip PAAR 1 Keywords Digital Landscape Architecture, 3D-Scanning, DTM, Planting Visualization, ArcGIS, Google SketchUp, Lenne3D, webgis, ESRI ArcGlobe, Medisolae-3D, Google Earth, MS Virtual Earth This study is being undertaken to support an appropriate tourism design and management of Dwejra Coastal Nature Park, one of the important tourist points in Malta. The main design idea is to enhance the facilities of the most popular tourist area of Gozo Island, taking into consideration its natural scenic beauty, in order to promote the concept of Eco Island Gozo. The area was a very close candidate for becoming a World Heritage Site, and was nominated for EU Natura The laser scanner data was taken and processed in 2004; the visualization work was started in December 2008 and will be finalized in July Abstract The final paper will describe the entire workflow from the original laser scan and terrain modeling (Fig 1) through the integration within the e-government project Medisolae-3D. The workflow diagram (Fig. 2) shows the actual working process of the visualization, step by step. For the GIS processes and the 3D, the software versions ArcGIS 9.2 and SketchUp 6 are used. The objective for the visualization is to generate a digital realistic situation of the inland sea of Dwejra Bay to be used interactively in a WebExplorer such as Google Map or ArcGlobe. The study intends to present a prototype for the entire workflow from laser scanning to interactive VR model in a WebGIS Explorer. The chosen site with a nearly vertical rim around the inland sea and a number of small individual buildings feature is a real task for the modelers. The tunnel connecting the inland sea with the Mediterranean Sea forces one to find solutions for real 3D modeling. In this study, first 3D scatter plots from laser scanning were taken and processed by PAASCHE & PETZSCH (2004). The scanner data was converted into dxf file format. The dxf data driven by the laser scanner capture was imported to SketchUp 6 in different files to handle it safely. The terrain model and the building model are kept in two different SketchUp files.

2 Virtualizing Boathouses in Dwejra, Malta for Access Through WebGIS 87 For the visualization of the SketchUp building model, pictures from all individual facades were taken. The photographs had to be matched to the different facades of the buildings. SketchUp was used for the further realistic visualization of the digital laser scan model. Fig 1 3D Modeling GIS Imaging Input Data Laserscanning/ Surveying Areal Photo Workflow Output 3D Object Building Map Building Textures 3D Plant Models Bird/ Flight view ESRI ArcScene Google SketchUp Lenne 3D DEM TIN Geodatabase 3D Model Geo Explorer ESRI ArcMap ESRI ArcCatalog Ortho Image Imaging Google Earth ESRI ArcGlobe Biosphere 3D Adobe Photoshop ESRI ArcGIS Explorer Fig. 2: Workflow from laser scanning to 3D modeling and visualization to WebGIS- Explorer

3 88 D. Langenhaun, E. Buhmann, M. Pietsch, S. Chougule and P. Paar Fig 3 Fig 4 Fig 5

4 Virtualizing Boathouses in Dwejra, Malta for Access Through WebGIS 89 Fig. 6: Model in ArcScene Fig. 7: Model in ArcScene with draped Arial Photo

5 90 D. Langenhaun, E. Buhmann, M. Pietsch, S. Chougule and P. Paar Fig. 8: Model in Google Earth For a realistic representation, the facades of the buildings are then textured with images taken from the facades. Figures 3 and 4 show the building model with draped textures, while Figure 5 shows the inside of the chapel. Three different level of detail had been used for the overview, the buildings and the inside of the building The 3D building model and the aerial photo could be matched as a basic SketchUp file. Next, the building texture model was added to the basic SketchUp file and exported to ESRI geodatabase while using an available plug in. A raster digital elevation model (DEM) was created by exporting the laser scan driven dxf elevation data of the terrain along with references into ArcMap. The model was then converted into TIN to a raster digital elevation model. The DEM driven from the stationary laser scanner was very detailed but originally had numerous artefacts. For the necessary smoothing and generalizing, 3D-Analyst was used. The DEM was generalized and a raster DEM was generated. In the next step, the geo-referenced aerial photo, the digital elevation model, and the textured building models were all incorporated in ArcScene (Fig. 6 and 7). Using ArcScene, it is possible that the model can have different presentations and flythroughs. In order to generate realistic vegetation, Lenné3D vegetation modeling software will be used. To present the potentials of the tourist site in WebGIS within the e-government Medisolae-3D project, the explorer of ESRI ArcGlobe, Google Earth and MS Virtual Earth will be used.

6 Virtualizing Boathouses in Dwejra, Malta for Access Through WebGIS 91 Fig. 9: Lenné3D Biosphere3D Landscape Scenery Globe, beta (Biosphere3D.org) The technical emphasis of this paper is to show the entire workflow from the initial laser scan to the virtual model in the web using today s standard software products. The study shows that the various needed software products can be combined. However the integration of models from product to product suffers from the different update versions that usually do not consider the updates of the plug-ins. In order to use this process in a normal GIS planning environment, means of automatic processes have to be found. The landscape architectural emphasis is to use the power of the web in order to promote more sensitive landscape managing. 3 References Bonazountas, Marc, Jörg Schaller, Giacomo Martirano, Cristina Mattos, Louis Roumeliotiss and Despina Kallidromitou (2009): MedIsolae-3D : Mediterranean Islands SDI and 3D Aerial Web-Navigation. In: Buhmann/Kieferle/Pietsch/Paar/Kretzler (Eds.) DIGITAL LANDSCAPE ARCHITECTURE 2009, Proceedings of Presented Papers. Anhalt University of Applied Sciences, Bernburg, Germany, May 2009 Paasche, Dominik & Thorsten Petzsch (2004): Einsatz des Laserscanners HDS 3000 zur Visualisierung der Dwejra Bay auf Gozo, Thesis in surveying at Anhalt University of Applied Sciences, Dessau, Germany