High-Fidelity Roadway Modeling and Simulation

Roads are an essential feature in our daily lives. With the advances in computing technologies, 2D and 3D road models are employed in many applications, such as computer games and virtual environments. Traditional road models were generated by professional artists manually using modeling software tools such as Maya and 3ds Max. This approach requires both highly specialized and sophisticated skills and massive manual labor. Automatic road generation based on procedural modeling can create road models using specially designed computer algorithms or procedures, reducing the tedious manual editing needed for road modeling dramatically. But most existing procedural modeling methods for road generation put emphasis on the visual effects of the generated roads, not the geometrical and architectural fidelity. This limitation seriously restricts the applicability of the generated road models. To address this problem, this paper proposes a high-fidelity roadway generation method that takes into account road design principles practiced by civil engineering professionals, and as a result, the generated roads can support not only general applications such as games and simulations in which roads are used as 3D assets, but also demanding civil engineering applications, which requires accurate geometrical models of roads. The inputs to the proposed method include road specifications, civil engineering road design rules, terrain information, and surrounding environment. Then the proposed method generates in real time 3D roads that have both high visual and geometrical fidelities. This paper discusses in details the procedures that convert 2D roads specified in shape files into 3D roads and civil engineering road design principles. The proposed method can be used in many applications that have stringent requirements on high precision 3D models, such as driving simulations and road design prototyping. Preliminary results demonstrate the effectiveness of the proposed method

Generative Street Addresses from Satellite Imagery

We describe our automatic generative algorithm to create street addresses from satellite images by learning and labeling roads, regions, and address cells. Currently, 75% of the world’s roads lack adequate street addressing systems. Recent geocoding initiatives tend to convert pure latitude and longitude information into a memorable form for unknown areas. However, settlements are identified by streets, and such addressing schemes are not coherent with the road topology. Instead, we propose a generative address design that maps the globe in accordance with streets. Our algorithm starts with extracting roads from satellite imagery by utilizing deep learning. Then, it uniquely labels the regions, roads, and structures using some graph- and proximity-based algorithms. We also extend our addressing scheme to (i) cover inaccessible areas following similar design principles; (ii) be inclusive and flexible for changes on the ground; and (iii) lead as a pioneer for a unified street-based global geodatabase. We present our results on an example of a developed city and multiple undeveloped cities. We also compare productivity on the basis of current ad hoc and new complete addresses. We conclude by contrasting our generative addresses to current industrial and open solutions. Keywords: road extraction; remote sensing; satellite imagery; machine learning; supervised learning; generative schemes; automatic geocodin

Analyse und Generierung von Straßennetzwerken mittels graphenbasierter Methoden

Der vorliegende Beitrag ist in zwei thematische Teilebereiche gegliedert. Der erste Teil beschäftigt sich mit der Analyse von Graphen, insbesondere von Graphen, die Straßennetzwerke repräsentieren. Hierzu werden Methoden aus der Graphentheorie angewendet und Kenngrößen aus der Space Syntax Methode ausgewertet. Ein Framework, welches basierend auf der Graphentheorie in Architektur und Stadtplanung Einzug gehalten hat, ist die Space Syntax Methode. Sie umfasst die Ableitung unterschiedlicher Kenngrößen eines Graphen bzw. Netzwerkes, wodurch eine Analyse für architektonische und stadtplanerische Zwecke ermöglicht wird. Der zweite Teil dieses Berichts beschäftigt sich mit der Generierung von Graphen, insbe-sondere der von Straßennetzwerkgraphen. Die generativen Methoden basieren zum Teil auf den gewonnenen Erkenntnissen der Analyse von Straßennetzwerken. Es werden unterschiedliche Ansätze untersucht, um verschiedene Parameterwerte zur Generierung von Straßengraphen festzulegen. Als Ergebnis der Arbeiten ist ein Softwaretool entstanden, welches es erlaubt, auf Grundlage einer Voronoi-Tesselierung realistische Straßennetzwerkgraphen zu erzeugen

Space colonisation based procedural road generation

Dissertação de mestrado em Computer ScienceProcedural generation of content has been studied for quite some time and it is increasingly relevant in scientific areas and in video-game and film industries. Procedural road layout generation has been traditionally approached using L-Systems, with some works exploring alternative avenues. Although originally conceived for biological systems modelling, the adequacy of L-Systems as a base for road generation has been demonstrated in several works. In this context, this work presents an alternative approach for procedural road layout generation that is also inspired by plant generation algorithms: space colonisation. In particular, this work uses the concept of attraction points introduced in space colonisation as its base to produce road layouts, both in urban and inter-city environments. As will be shown, the usage of attraction points provides an intuitive way to parameterise a road layout. The original Space Colonization Algorithm (SCA) generates a tree like structure, but in this work, the extensions made aim to fully generate a inter-connected road network. As most previous methods the method has two phases. A first phase generates what is mostly a tree structure growing from user defined road segments. The second phase performs the inter connectivity among the roads created in the first phase. The original SCA parameters such as the killradius help to control the capillarity of the road layout, the number of attraction points used by each segment will dictate its relevance establishing a road hierarchy naturally dependent on the distribution of the attraction points on the terrain. An angle control allows the creation of grid like or more organic road layouts. The distribution of the attraction points in the terrain can be conditioned by boundary maps, containing parks, sea, rivers, and other forbidden areas. Population density maps can be used to supply an explicit probabilistic distribution to the attraction points. Flow-fields can be used to dictate the flow of the road layout. Elevation maps provide an additional restriction regarding the steepness of the roads. The tests were executed within a graphic toolbox developed simultaneously. The results are exported to a geographical information file format, GeoJSON, and then maps are rendered using a geospatial visualisation and processing framework called Mapnik. For the most part, parameter settings were intuitively reflected on the road layout and this method can be seen as a first step towards fully exploring the usage of attraction points in the context of road layout.Gradualmente a geração procedimental de conteúdo tem-se tornado cada vez mais relevante, sendo maioritariamente aplicada em industrias como a dos vídeo-jogos e cinema. No que toca à geração procedimental de redes de estradas, grande parte das abordagens em torno deste tema são baseadas em L-Systems. Embora a área de aplicação dos L-Systems tenha sido originalmente para produzir modelos de sistemas biológicos, mostrou também ser um algoritmo adequado para a geração procedimental de redes de estradas. Este trabalho apresenta uma abordagem alternativa à geração procedimental de redes de estradas que também é inspirada num algoritmo procedimental de geração de plantas, colonização espacial, utilizando o conceito de pontos de atracão como base para gerar padrões de estradas. Como será demonstrado, a utilização de pontos de atracão fornece uma maneira intuitiva de parametrizar um padrão de estradas desejado. Como a maioria dos trabalhos feitos nesta área, este método tem duas fases. A primeira fase gera uma rede semelhante a uma árvore criada a partir de um ou mais segmentos iniciais da rede determinados pelo utilizador. A segunda fase trata de interligar as estradas geradas na primeira fase. Os parâmetros iniciais do algoritmo de colonização espacial, como o kill radius, ajudam a controlar a capilaridade da rede, os pontos de atracão que influenciam cada segmento irão ditar a sua relevância na rede geral, estabelecendo a noção de hierarquia de estradas, dependendo da distribuição de pontos de atracão no terreno. O controlo do ângulo entre segmentos permite a criação de padrões de estradas tanto em forma de grelha como padrões mais orgânicos. A distribuição dos pontos de atracão no terreno pode ser influenciada por mapas de fronteira, que contem as áreas válidas e/ou inválidas, como parques, mar, rios, e outras áreas proibidas. Mapas de densidade populacional podem ser usados para fornecer uma distribuição probabilística dos pontos de atracão. Campos de forças, podem ser usados para ditar o fluxo da rede de estradas. Mapas de elevação oferecem uma restrição adicional tendo em conta a inclinação das estradas. De um modo geral, as definições de parâmetros refletiram-se de um modo intuitivo nos padrões de redes de estradas gerados, e este trabalho pode ser considerado como um primeiro passo na exploração do conceito de pontos de atracão na área da geração de redes de estradas

A Survey of Procedural Techniques for City Generation

The computer game industry requires a skilled workforce and this combined with the complexity of modern games, means that production costs are extremely high. One of the most time consuming aspects is the creation of game geometry, the virtual world which the players inhabit. Procedural techniques have been used within computer graphics to create natural textures, simulate special effects and generate complex natural models including trees and waterfalls. It is these procedural techniques that we intend to harness to generate geometry and textures suitable for a game situated in an urban environment. Procedural techniques can provide many benefits for computer graphics applications when the correct algorithm is used. An overview of several commonly used procedural techniques including fractals, L-systems, Perlin noise, tiling systems and cellular basis is provided. The function of each technique and the resulting output they create are discussed to better understand their characteristics, benefits and relevance to the city generation problem. City generation is the creation of an urban area which necessitates the creation of buildings, situated along streets and arranged in appropriate patterns. Some research has already taken place into recreating road network patterns and generating buildings that can vary in function and architectural style. We will study the main body of existing research into procedural city generation and provide an overview of their implementations and a critique of their functionality and results. Finally we present areas in which further research into the generation of cities is required and outline our research goals for city generation