VIRTUAL 3D CITY MODEL BY USING GEOMATICS TECHNIQUES

Abstract

3D city model is a three dimensional digital representation of a city. In recent time, 3D city model creation demand is increasing for various engineering and non-engineering applications. Geomatics is an umbrella term used for mapping techniques. Photogrammetry (Close Range, Aerial & Satellite photogrammetry) and lasergrammetry are the main geomatics techniques to create virtual 3D city model. Cost, time, labour and accuracy are the key issue for any 3D city model related project. Now a days, various software packages are available in the market to create 3D city model by using various methods and techniques. Each and every technique has some positive and some negative aspects. These techniques are not complete itself to create 3D city model. Limited study and research work has been done in India for 3D city modeling. For 3D city model generation, limited literature and very few methods are available. Due to these main problems, a new methods/process is required for 3D city model generation. All over the world, many people and researchers are working to create virtual 3D city model by using geomatics techniques. In this research work, first; analyze the potential and limitations of the SketchUp based 3D city model, CityEngine based 3D city model and Photomodeler based 3D city model. These softwares have some advantages with limitations too and not much suitable for 3D city modeling. Advantages and limitations also discussed for these approaches. In this research approach, a methodology is developed to create image based virtual 3D city model using close range photogrammetric principles. A simple video camera used for video recording of a city from indigenously developed a multi-camera setup system. From these video, images frames were created. These image frames were used for 3D processing based on close range photogrammetry and computer vision based methods. After 3D processing of these image frames, a virtual 3D model of an area has been created. This 3D model was further exported to next data combination processing. From this method, a virtual 3D model of study area has been created. In this research work, study area was Civil Engineering Department at Indian Institute of Technology, Roorkee, (Uttrakhand) India. ii This developed method is better and validated. It is a simple and accurate method. The methodology proved the effectiveness of geomatics techniques mainly close range photogrammetry. For this method, user should have knowledge of geomatics techniques mainly close range photogrammetry. Most of the processing is automatic, that save the cost, time and labour work of project. In this method, the accuracy of 3D model depends on measurement of dimensions and it’s scaling. Thus 3D model is near to accurate value. Texture quality is also good to give photo-realistic look. This method is also suitable for high density building area. This method also has very few limitations. At the end, some conclusions and recommendations for future work are also discussed. This kind of 3D city model is useful for various engineering and non-engineering applications such as – Planning for civil engineering and architecture related projects, 3D Transportation planning, 3D navigation, virtual tourism, e-governance, disaster management planning and preservation of historical buildings and forts. This method is also useful for municipality to encroachment identification.