Search

Modelling a 3D city poses an interesting challenge. To create a virtual city, a road pattern has to be designed and a large number of buildings need to be generated. Every urban place has a road network, often a superimposed pattern plan that serves a population density and buildings which follow statutory rules. This patterned behaviour of the city is why it is possible to develop rules or “computational instructions,” to generate city models. In this article, we are going to discuss how to use procedural modelling and CityEngine, a rule-based application commonly used in the movie industry and gaming to produce vast realistic cityscapes, for regional and urban planning via an urban analytics approach. Unlike cinema’s imaginary worlds, cities have real-life population dependencies that need to be modelled for the development of planning scenarios. The goal is then to use the generative properties of the procedural modelling approach, along with population prediction models, to create informed 3D city scenarios. Instead of designing solutions, the user can use interactive parameters to affect the 3D model globally, thus enabling virtual cities to become active simulators for planning. Using urban analytics and generative environments, procedural cities may be able to create a “teaser” of different versions of how the city would look like in the future.

Tradicionalmente, el LiDAR y la fotogrametría se conciben como fuentes de información independientes ampliamente utilizadas para el mapeo urbano de las ciudades, cada uno con sus ventajas y desventajas. El avance tecnológico permitió la introducción en el mercado de un sistema, sensor hibrido CityMapper-2 de la Compañía Leica Geosystems, que permite adquirir de manera simultánea datos LiDAR en conjunto con imágenes aéreas. El objetivo del presente trabajo es evaluar el potencial de los datos capturados con este sensor en la Ciudad de Pamplona, para generar distintos productos geoespaciales como nubes de puntos, modelos digitales de elevaciones, mallas 3D, mallas 2.5D y ortofotos verdaderas. La metodología propuesta consiste en analizar las diferencias de productos generados mediante el software Agisoft Metashape con productos de referencia generado a través del software nFrames. Se establecen diferentes comparaciones, a partir de la selección de las mejores pruebas, para destacar el aporte de cada fuente de información a los productos obtenidos. Los resultados evidencian que en zonas urbanas la combinación con información LiDAR otorga mayor calidad al producto generado, en especial para zonas que presentan oclusiones con calles muy estrechas, zonas donde hay sombras y donde hay mucha presencia de árboles. Traditionally, LiDAR and photogrammetry are conceived as widely used independent sources of information for urban mapping of cities, each with its advantages and disadvantages. The technological advance achieved the introduction in the market of a system, the CityMapper-2 hybrid sensor from the Leica Geosystems Company, which allows simultaneous acquisition of LiDAR data in conjunction with aerial images. The objective of this work is to evaluate the potential of the data captured with this sensor in the City of Pamplona, to generate different geospatial products such as point clouds, digital elevation models, 3D meshes, 2.5D meshes and true orthophotos. The proposed methodology consists of analyzing the differences of products generated by Agisoft Metashape software with reference products generated through nFrames software. Different comparisons were found, based on the best test, to highlight the report of each source of information to the products obtained. The results show that in urban areas the combination with LiDAR information gives higher quality to the generated product, especially for areas that present occlusions with very narrow streets, areas where there is shadow and where there are a lot of trees Máster Universitario en Sistemas de Información Geográfica y Teledetección por la Universidad Pública de Navarra Informazio Geografikoko Sistemetako eta Teledetekzioko Unibertsitate Masterra Nafarroako Unibertsitate Publikoan

Solar accessibility, defined as the solar irradiation received in a spatial and temporal domain, is increasingly becoming a practical demand in a variety of applications, especially in dense and high-rise urban areas where people prefer natural daylighting accommodations and offices and enterprises desire rooftops with high exposure to sun for photovoltaic cells. However, new buildings may substantial alter spatio-temporal solar distribution and obstruct exposure to solar power significantly. Thus, providing an accurate quantification of how solar accessibility is impacted by a developing urban environment is a key step in the development of sustainable cities. Motivated by this observation, a solar irradiation estimation model has been designed, which allows solar radiation from a particular elevation and azimuth to pass through urban surfaces modelled as 3D polygons, resulting in the creation of 3D shadow surfaces. As such, the urban surfaces can also be represented as 3D point clouds of irradiations determined by both solar radiation and shadow. By applying the model to existing and planned urban environment, it is possible to estimate the transformation of solar accessibility at the district scale. As a case study, a master plan for the Kowloon East district proposed by the Hong Kong government has been considered, and an application of the propose methodology found that new buildings to be built in the district can obtain considerable solar energy, while having a marginal impact on existing buildings. This case study suggests that the model can be used in many other cities for a variety proposes.