Urban digital twin (UDT) technology can be used to digitize physical urban spaces. Previous UDT or smart city research reconstructed the three-dimensional topography of urban spaces, buildings, and facilities. They collected various multimodal sensor data from cities and monitored conditions such as temperature, humidity, fine dust, and real-time road traffic. However, these studies lacked ways to manage individual mobility data, such as those of the vehicles and pedestrians, which constitute major components of a city. Here, we propose a geospatial platform based on the universal game engine Unity3D, which manages large-scale individual mobility data for a UDT platform. The proposed platform stores and manages individual vehicles or pedestrians using information from public closed-circuit television. It also allows the generation of long-term route information for a unique vehicle based on its license plate. We also propose methods to anonymize license plates, to ensure the security of individuals, and to compress individual mobility data. Unique UDT models with individual mobility functionalities can be built and visualized using our proposed geospatial platform.

The steady evolution of mapping technology is leading to an increasing availability of multi-sensory geo-spatial datasets, such as data acquired by single-head frame cameras, multi-head frame cameras, line cameras, and light detection and ranging systems, at a reasonable cost. The complementary nature of the data collected by these systems makes their integration to obtain a complete description of the object space. However, such integration is only possible after accurate co-registration of the collected data to a common reference frame. The registration can be carried out reliably through a triangulation procedure which considers the characteristics of the involved data. This paper introduces algorithms for a multi-primitive and multi-sensory triangulation environment, which is geared towards taking advantage of the complementary characteristics of spatial data available from the above mentioned sensors. The triangulation procedure ensures the alignment of involved data to a common reference frame. The devised methodologies are tested and proven efficient through experiments using real multi-sensory data.

This paper introduces an automated method for building height recovery through the integration of high‐resolution satellite images and digital vector maps. A cross‐correlation matching method along the vertical line locus on the Ikonos images was deployed to recover building heights. The rational function models composed of rational polynomial coefficients were utilized to create a stereopair of the epipolar resampled Ikonos images. Building footprints from the digital maps were used for locating the vertical guideline along the building edges. The digital terrain model (DTM) was generated from the contour layer in the digital maps. The terrain height derived from the DTM at each foot of the buildings was used as the starting location for image matching. At a preset incremental value of height along the vertical guidelines derived from vertical line loci, an evaluation process that is based on the cross‐correlation matching of the images was carried out to test if the top of the building has reached where maximum correlation occurs. The accuracy of the reconstructed buildings was evaluated by the comparison with manually digitized 3D building data derived from aerial photographs.

This study developed an API for imagery map mobile web service to link geo-tagged information using HTML5 and analyzed it to draw technical issue of the imagery map mobile service using HTML5. HTML5 is not subordinate to a platform; the development and maintenance cost is low; and it is highly compatible so it is evaluated to be an appropriate standard to offer mobile imagery map. Using Geolocation, map control, offline browsing, and multimedia POI capabilities of HTML5 were used for the imagery map mobile web service, and test analysis was conducted for the realized API regarding initial service loading time, zooming time, and panning time. In the result, HTML5 increased the convenience and versatility and obtained similar levels in map control performance comparing to a service using existing methods. Through this process, technical issues were drawn in terms of using HTML5 such as obtaining user location information, map rotation, mPOI, imagery map service, video & audio execution, and source distribution. These issues will be solved if HTML5 specifications are stabilized and mobile web browsers fully support HTML5 specifications.