Semi-automated modeling approaches to route selection in GIS

As an alternative to traditional graphical intuitive approaches (GIA), a semi-automated modeling approach (SMA) can more efficiently identify linear routes by using powerful iterative and automated methods. In this research, two case studies were investigated to examine critical issues relating to the accuracy and effectiveness of raster-defined algorithmic approaches to linear route location. The results illustrate that different shortest-path algorithms do not necessarily result in markedly different linear routes. However, differing results can occur when using different neighboring-cell links in the cell-based route network construction. Cell-based algorithmic approaches in both Arc/Info and IDRISI software generate very similar results which are comparable to linear modeling with greater than eight neighboring-cell links. Given a specific shortest-path algorithm and its route searching technique, the use of a finer spatial resolution only results in a narrower and smoother route corridor. Importantly, cost surface models can be generated to represent differing cumulative environmental \u27costs\u27 or impacts in which different perceptions of environmental cost can be simulated and evaluated.;Three different simulation techniques comprising Ordered Weighted Combination models (OWC), Dynamic Decision Space (DDS), and Gateway-based approaches, were used to address problems associated with concurrent and dynamic changes in multi-objective decision space. These approaches provide efficient and flexible simulation capability within a dynamic and changing decision space. When aggregation data models were used within a Gateway approach the match of resulting routes between GIA and SMA analyses is close. The effectiveness of SMA is greatly limited when confronted by extensive linear and impermeable barriers or where data is sparse. Overall, achieving consensus on environmental cost surface generation and criteria selection is a prerequisite for a successful SMA outcome. It is concluded that SMA has several positive advantages that certainly complement a GIA in linear route siting and spatial decision-making

The development and deployment of walkability assessment models for built environments

To encourage walking behavior, revising a built environment to be walkable is recognized as a necessity for influencing a broader audience while also having a long-term effect. Walkability, which indicates the friendliness of walking in a built environment, helps concerning parties to understand a urban context and make informative decisions when building walkable neighborhoods. Walkability is a fusion of different environment characteristics (e.g. sidewalk quality) influential to walking. Multiple instruments have been developed to measure perceived walkability by conducting surveys. However, this process is expensive and time-consuming. Matured GIS technologies together with extensive accessible data enable analysts to measure walkability objectively. While it is considerably inexpensive and time efficient, measuring walkability objectively has several challenging areas to tackle: the environmental characteristics to be considered, the methods to evaluate these characteristics, and the data availability to conduct the evaluation. To date, no existing model addresses those aspects appropriately. This thesis has developed models to objectively evaluate walkability for neighborhoods and walking routes. Through examining empirical studies that explored the relationship between walking and environment characteristics, this thesis has identified a few characteristics that are influential to walking and incorporated them into the area based walkability evaluation model: population density, destination accessibility, land use mix, walking infrastructure quality, aesthetics, traffic safety and transit accessibility. The importance of these characteristics changes when targeting different walking purposes (recreational or transportation), population groups, geographic locations and cultural contexts. By weighing each characteristic accordingly, the model adapts to different study contexts. The weights should be adjusted based on expert knowledge or by benchmarking empirical studies conducted in similar contexts (e.g. similar urban setting). For evaluating walkability for walking routes, Dijkstra's algorithm is adopted to identify the walkable routes by minimizing the cost associated with the routes. This cost is defined by route distance, street type (e.g. highway, sidewalk), infrastructure quality and facilities along the routes. As a case study, walkability is evaluated for the city of Helsinki. The implementation of the models has two purposes: 1) to provide a benchmark for analysts who intend to apply the model to other contexts, 2) to provide the environment quality information of Helsinki to concerning parties. Data processing, characteristics assessment, and walkability evaluation are described in detail to fulfill the first purpose. Secondly, a web application was developed to provide an accessible service for users to view the environment quality information including walkability. While walkability varies for individuals due to their personal preferences and needs, this service also allows customization by providing functionality to adjust weights of characteristics that are used to define walkability

Enhancing OpenStreetMap for the Assessment of Critical Road Infrastructure in a Disaster Context

Die Häufigkeit von Naturkatastrophen nimmt weltweit zu, was zu immensen Schäden an kritischer Straßeninfrastruktur und deren Funktionalität führen kann. Daher ist es von entscheidender Bedeutung, die Funktionalität kritischer Straßeninfrastruktur vor, während und nach einer Katastrophe zu beurteilen. Dazu werden globale Straßendaten benötigt, die für die Routenplanung nutzbar sind. OpenStreetMap (OSM) stellt globale Straßennetzdaten zur Verfügung, die kostenlos und frei zugänglich sind. Allerdings ist die Verwendung der OSM Straßendaten für Routenplanungsanwendungen oft eine Herausforderung. Das übergeordnete Ziel dieser Arbeit ist die Entwicklung eines generischen, mehrskaligen Konzepts zur Analyse kritischer Straßeninfrastrukturen im Kontext von Naturgefahren unter Verwendung von OSM Daten. Dafür werden zwei aufeinander folgende Forschungsziele aufgestellt: (i) die Verbesserung der Routingfähigkeit von OSM Daten und (ii) die Bewertung kritischer Straßeninfrastruktur im Kontext von Naturgefahren. Daraus resultiert die Gliederung dieser Arbeit in zwei Hauptteile, die jeweils den Forschungszielen entsprechen. Im ersten Teil dieser Arbeit wird die Nutzbarkeit von OSM Daten für Routing Anwendungen verbessert. Zunächst wird dafür die Qualität des OSM Straßennetzwerks im Detail analysiert. Dabei werden zwei große Herausforderungen im Bereich der Anwendbarkeit von OSM Daten für die Routenplanung identifiziert: fehlende Geschwindigkeitsangaben und Fehler in der Straßenklassifizierung. Um die erste Herausforderung zu bewältigen, wird ein FuzzyFramework zur Geschwindigkeitsschätzung (Fuzzy-FSE) entwickelt, welches eine Fuzzy Regelung zur Schätzung der Durchschnittsgeschwindigkeit einsetzt. Diese Fuzzy Regelung basiert auf den Parametern Straßenklasse, Straßenneigung, Straßenoberfläche und Straßenlänge einsetzt. Das Fuzzy-FSE besteht aus zwei Teilen: einer Regel- und Wissensbasis, die über die Zugehörigkeitsfunktionen für den Ausgangsparameter Geschwindigkeit entscheidet, und mehrere Fuzzy-Regelsysteme, welche die resultierende Durchschnittsgeschwindigkeit berechnen. Die Ergebnisse zeigen, dass das Fuzzy-FSE auch bei ausschließlicher Verwendung von OSM Daten eine bessere Leistung erbringt als bestehende Methoden. Die Herausforderung der fehlerhaften Straßenklassifizierung wird durch die Entwicklung eines neuartigen Ansatzes zur Erkennung von Klassifizierungfehlern in OSM angegangen. Dabei wird sowohl nach nicht verbundenen Netzwerkteilen als auch nach Lücken im Straßennetzwerk gesucht. Verschiedene Parameter werden in einem Bewertungssystem kombiniert, um eine Fehlerwahrscheinlichkeit zu erhalten. Auf Basis der Fehlerwahrscheinlichkeit kann ein menschlicher Nutzer diese Fehler überprüfen und korrigieren. Die Ergebnisse deuten einerseits darauf hin, dass an Lücken mehr Klassifizierungsfehler gefunden werden als an nicht verbundenen Netzwerkteilen. Andererseits zeigen sie, dass das entwickelte Bewertungssystem bei einer benutzergesteuerten Suche nach Lücken zu einem schnellen Aufdecken von Klassifizierungsfehlern verwendet werden kann. Aus dem ersten Teil dieser Arbeit ergibt sich somit ein erweiterter OSM Datensatz mit verbesserter Routingfähigkeit. Im zweiten Teil dieser Arbeit werden die erweiterten OSM Daten zur Bewertung der kritischen Straßeninfrastruktur im Katastrophenkontext verwendet. Dazu wird der zweite Teil des generischen, mehrskaligen Konzepts entwickelt, das aus mehreren, miteinander verbundenen Modulen besteht. Ein Modul implementiert zwei Erreichbarkeitsindizes, welche verschiedene Aspekte der Erreichbarkeit im Straßennetzwerk hervorheben. In einem weiteren Modul wird ein grundlegendes Modell der Verkehrsnachfrage entwickelt, welches den täglichen interstädtischen Verkehr ausschließlich auf der Grundlage von OSM Daten schätzt. Ein drittes Modul verwendet die oben beschriebenen Module zur Schätzung verschiedener Arten von Auswirkungen von Naturkatastrophen auf das Straßennetzwerk. Schließlich wird in einem vierten Modul die Vulnerabilität des Straßennetzes gegenüber weiteren Schäden bei Langzeitkatastrophen analysiert. Das generische Konzept mit allen Modulen wird exemplarisch in zwei verschiedenen Regionen für zwei Waldbrandszenarien angewendet. Die Ergebnisse der Fallstudien zeigen, dass das Konzept ein wertvolles, flexibles und global anwendbares Instrument für Regionalplaner und Katastrophenmanagement darstellt, das länder- bzw. regionenspezifische Anpassungen ermöglicht und gleichzeitig wenig Daten benötigt

Quiet paths for people : developing routing analysis and Web GIS application

Altistuminen saasteille saattaa vähentää merkittävästi aktiivisten liikkumismuotojen, kuten kävelyn ja pyöräilyn terveyshyötyjä. Yksi liikenteestä johtuvista saasteista on melu, joka voi aiheuttaa terveyshaittoja, kuten kohonnutta verenpainetta ja stressiä. Aikaisemmissa tutkimuksissa ja selvityksissä melulle altistumista on arvioutu yleensä kotipaikan suhteen ja liikkumisen aikana tapahtuva altistus on jäänyt vähemmälle huomiolle. Koska liikkumisen aikainen (dynaaminen) melualtistus saattaa muodostaa merkittävän oan kaupunkilaisten päivittäisestä kokonaismelualtistuksesta, tarvitaan kehittyneempiä menetelmiä dynaamisen melualtistuksen arvioimiseen ja vähentämiseen. Tässä tutkielmassa kehitin kävelyn reititysmenetelmän ja sovelluksen, jolla voi 1) etsiä lyhimmän reitin, 2) mallintaa kävelyn aikaisen melualtistuksen ja 3) löytää vaihtoehtoisia, hiljaisempia reittejä. Sovellus hyödyntää OpenStreetMap-tieverkostoaineistoa ja mallinnettua aineistoa tieliikenteen tyypillisistä päiväajan melutasoista. Reitinetsintä perustuu kehittämääni melukustannusfunktioon ja alhaisimman kustannuksen reititysanalyysiin. Melukustannukset lasketaan sovelluksessa lukuisilla eri meluherkkyyskertoimilla, minkä ansiosta sovellus löytää useita vaihtoehtoisia (hiljaisempia) reittejä. Jotta eri reittien meluisuutta (melualtistuksia) voidaan vertailla, kehitin sarjan melualtistusindeksejä. Tapaustutkimuksessa tutkin Helsingistä tehtävien työmatkojen aikaisia melualtistuksia; selvitin rekistereihin perustuvien työmatkojen mukaiset joukkoliikennereitit ja tutkin reittien kävelyosuuksien aikaisia melualtistuksia reitittämällä kävelyreitit uudestaan kehittämälläni reitityssovelluksella. Lisäksi tutkin hiljaisempien reittivaihtoehtojen mahdollistamia vähennyksiä melualtistuksissa tapaustutkimuksessa mallinnetuilla kävelyreiteillä. Tapaustutkimuksen tulokset indikoivat, että tyypilliset dynaamiset melualtistukset vaihtelevat huomattavasti eri asuinpaikkojen välillä. Toisaalta merkittävä osa melulle altistumisesta on mahdollista välttää hiljaisemmilla reittivaihtoehdoilla; tilanteesta riippuen, hiljaisemmat reitit tarjoavat keskimäärin 12–57 % vähennyksen altistuksessa yli 65 dB melutasoille ja 1.6–9.6 dB keskimääräisen vähennyksen reittien keskimääräisessä melutasossa. Altistuksen mahdolliseen vähennykseen näyttäisivät vaikuttavan ainakin 1) melualtistuksen suuruus lyhimmällä (ts. verrokki) reitillä, 2) lyhimmän reitin pituus, eli etäisyys lähtö- ja kohdepisteen välillä reititysgraafissa ja 3) hiljaisemman reitin pituus lyhimpään reittiin verrattuna. Julkaisin hiljaisten kävelyreittien reitityssovelluksen avoimena web-rajapintapalveluna (API - Application Programming Interface) ja kehitin hiljaisten kävelyreittien reittioppaan mobiilioptimoituna web-karttasovelluksena. Kaikki tutkielmassa kehitetyt menetelmät ja lähdekoodit ovat avoimesti saatavilla GitHub-palvelussa. Yksilöiden ja kaupunkisuunnittelijoiden tietoutta dynaamisesta altistuksesta melulle (ja muille saasteille) tulisi lisätä kehittämällä altistusten arviointiin ja vähentämiseen kehittyneempiä analyyseja ja sovelluksia. Tässä tutkielmassa kehitetty web-karttasovellus havainnollistaa hiljaisten reittien reititysmenetelmän toimivuutta tosielämän tilanteissa ja voi näin ollen auttaa jalankulkijoita löytämään hiljaisempia, ja siten terveellisempiä, reittivaihtoehtoja. Kun ympäristöllisiin altistuksiin perustuvaa reitinetsintää kehitetään pidemmälle, tulisi pyrkiä huomioimaan useampia erillisiä altistuksia samanaikaisesti ja siten reitittämään yleisesti ottaen terveellisempiä reittejä.It is likely that journey-time exposure to pollutants limit the positive health effects of active transport modes (e.g. walking and cycling). One of the pollutants caused by vehicular traffic is traffic noise, which is likely to cause various negative health effects such as increased stress levels and blood pressure. In prior studies, individuals’ exposure to community noise has usually been assessed only with respect to home location, as required by national and international policies. However, these static exposure assessments most likely ignore a substantial share of individuals’ total daily noise exposure that occurs while they are on the move. Hence, new methods are needed for both assessing and reducing journey-time exposure to traffic noise as well as to other pollutants. In this study, I developed a multifunctional routing application for 1) finding shortest paths, 2) assessing dynamic exposure to noise on the paths and 3) finding alternative, quieter paths for walking. The application uses street network data from OpenStreetMap and modeled traffic noise data of typical daytime traffic noise levels. The underlying least cost path (LCP) analysis employs a custom-designed environmental impedance function for noise and a set of (various) noise sensitivity coefficients. I defined a set of indices for quantifying and comparing dynamic (i.e. journey-time) exposure to high noise levels. I applied the developed routing application in a case study of pedestrians’ dynamic exposure to noise on commuting related walks in Helsinki. The walks were projected by carrying out an extensive public transport itinerary planning on census based commuting flow data. In addition, I assessed achievable reductions in exposure to traffic noise by taking quieter paths with statistical means by a subset of 18446 commuting related walks (OD pairs). The results show significant spatial variation in average dynamic noise exposure between neighborhoods but also significant achievable reductions in noise exposure by quieter paths; depending on the situation, quieter paths provide 12–57 % mean reduction in exposure to noise levels higher than 65 dB and 1.6–9.6 dB mean reduction in mean dB (compared to the shortest paths). At least three factors seem to affect the achievable reduction in noise exposure on alternative paths: 1) exposure to noise on the shortest path, 2) length of the shortest path and 3) length of the quiet path compared to the shortest path. I have published the quiet path routing application as a web-based quiet path routing API (application programming interface) and developed an accompanying quiet path route planner as a mobile-friendly web map application. The online quiet path route planner demonstrates the applicability of the quiet path routing method in real-life situations and can thus help pedestrians to choose quieter paths. Since the quiet path routing API is open, anyone can query short and quiet paths equipped with attributes on journey-time exposure to noise. All methods and source codes developed in the study are openly available via GitHub. Individuals’ and urban planners’ awareness of dynamic exposure to noise and other pollutants should be further increased with advanced exposure assessments and routing applications. Web-based exposure-aware route planner applications have the potential to help individuals to choose alternative, healthier paths. When developing exposure-based routing analysis further, attempts should be made to enable simultaneously considering multiple environmental exposures in order to find overall healthier paths

Susceptibility Modeling and Mission Flight Route Optimization in a Low Threat, Combat Environment

Movement and transportation systems are a primary topic in the study of humans and their relationship with the environment. Only a few modes of transportation allow for nearly full freedom of movement that is unconstrained by rigid nodes and networks. Individual human travel (walking, climbing, swimming, etc.) is one example while rotorcraft travel is another. Although other criteria constrain movement, independence from a network allows for a unique examination of human spatial decision-making and choice behavior. This research analyzes helicopter flight route planning in a low threat combat environment with respect to geography. The particular problem addressed, which ultimately concerns the quantitative representation and mapping of helicopter susceptibility in a low threat, combat environment, is assisted by a Geographic Information System (GIS). Prior susceptibility research on helicopters is combined with the spatial analytical functions of a GIS to cartographically model three dimensional flight corridors and routes across four separate areas. GIS optimized flight routing plans that minimize helicopter susceptibility (maximize capability to avoid threats) are then compared to the conventional routes produced by human flight route planners using existing techniques. Findings indicate that although the GIS routes reduce susceptibility costs, they concomitantly decrease route diversity. There was no significant evidence that experience, expertise, landscape familiarity, age, or the amount of time taken to plan had any effect on the spatial character of the routes. Several spatial similarities between conventionally planned routes and GIS optimized routes were revealed that expose potential perceptual limitations imposed by the conventional flight planning paradigm. Implementation of geospatial technology could help eliminate these restrictions

Does Time Smoothen Space? Implications for Space-Time Representation

The continuous nature of space and time is a fundamental tenet of many scientific endeavors. That digital representation imposes granularity is well recognized, but whether it is possible to address space completely remains unanswered. This paper argues Hales' proof of Kepler's conjecture on the packing of hard spheres suggests the answer to be "no", providing examples of why this matters in GIS generally and considering implications for spatio-temporal GIS in particular. It seeks to resolve the dichotomy between continuous and granular space by showing how a continuous space may be emergent over a random graph. However, the projection of this latent space into 3D/4D imposes granularity. Perhaps surprisingly, representing space and time as locally conjugate may be key to addressing a "smooth" spatial continuum. This insight leads to the suggestion of Face Centered Cubic Packing as a space-time topology but also raises further questions for spatio-temporal representation

Road distance and travel time for spatial urban modelling

Interactions within and between urban environments include the price of houses, the flow of traffic and the intensity of noise pollution, which can all be restricted by various physical, regulatory and customary barriers. Examples of such restrictions include buildings, one-way systems and pedestrian crossings. These constrictive features create challenges for predictive modelling in urban space, which are not fully captured when proximity-based models rely on the typically used Euclidean (straight line) distance metric. Over the course of this thesis, I ask three key questions in an attempt to identify how to improve spatial models in restricted urban areas. These are: (1) which distance function best models real world spatial interactions in an urban setting? (2) when, if ever, are non-Euclidean distance functions valid for urban spatial models? and (3) what is the best way to estimate the generalisation performance of urban models utilising spatial data? This thesis answers each of these questions through three contributions supporting the interdisciplinary domain of Urban Sciences. These contributions are: (1) the provision of an improved approximation of road distance and travel time networks to model urban spatial interactions; (2) the approximation of valid distance metrics from non-Euclidean inputs for improved spatial predictions and (3) the presentation of a road distance and travel time cross-validation metric to improve the estimation of urban model generalisation. Each of these contributions provide improvements against the current state-of-the-art. Throughout, all experiments utilise real world datasets in England and Wales, such datasets contain information on restricted roads, travel times, house sales and traffic counts. With these datasets, I display a number of case studies which show up to a 32% improved model accuracy against Euclidean distances and in some cases, a 90% improvement for the estimation of model generalisation performance. Combined, the contributions improve the way that proximity-based urban models perform and also provides a more accurate estimate of generalisation performance for predictive models in urban space. The main implication of these contributions to Urban Science is the ability to better model the challenges within a city based on how they interact with themselves and each other using an improved function of urban mobility, compared with the current state-of-the-art. Such challenges may include selecting the optimal locations for emergency services, identifying the causes of traffic incidents or estimating the density of air pollution. Additionally, the key implication of this research on geostatistics is that it provides the motivation and means of undertaking non-Euclidean based research for non-urban applications, for example predicting with alternative, non-road based, mobility patterns such as migrating animals, rivers and coast lines. Finally, the implication of my research to the real estate industry is significant, in which one can now improve the accuracy of the industry's state-of-the-art nationwide house price predictor, whilst also being able to more appropriately present their accuracy estimates for robustness

Methodology and Algorithms for Pedestrian Network Construction

With the advanced capabilities of mobile devices and the success of car navigation systems, interest in pedestrian navigation systems is on the rise. A critical component of any navigation system is a map database which represents a network (e.g., road networks in car navigation systems) and supports key functionality such as map display, geocoding, and routing. Road networks, mainly due to the popularity of car navigation systems, are well defined and publicly available. However, in pedestrian navigation systems, as well as other applications including urban planning and physical activities studies, road networks do not adequately represent the paths that pedestrians usually travel. Currently, there are no techniques to automatically construct pedestrian networks, impeding research and development of applications requiring pedestrian data. This coupled with the increased demand for pedestrian networks is the prime motivation for this dissertation which is focused on development of a methodology and algorithms that can construct pedestrian networks automatically. A methodology, which involves three independent approaches, network buffering (using existing road networks), collaborative mapping (using GPS traces collected by volunteers), and image processing (using high-resolution satellite and laser imageries) was developed. Experiments were conducted to evaluate the pedestrian networks constructed by these approaches with a pedestrian network baseline as a ground truth. The results of the experiments indicate that these three approaches, while differing in complexity and outcome, are viable for automatically constructing pedestrian networks

Application of Geographic Information Systems

The importance of Geographic Information Systems (GIS) can hardly be overemphasized in today’s academic and professional arena. More professionals and academics have been using GIS than ever – urban & regional planners, civil engineers, geographers, spatial economists, sociologists, environmental scientists, criminal justice professionals, political scientists, and alike. As such, it is extremely important to understand the theories and applications of GIS in our teaching, professional work, and research. “The Application of Geographic Information Systems” presents research findings that explain GIS’s applications in different subfields of social sciences. With several case studies conducted in different parts of the world, the book blends together the theories of GIS and their practical implementations in different conditions. It deals with GIS’s application in the broad spectrum of geospatial analysis and modeling, water resources analysis, land use analysis, infrastructure network analysis like transportation and water distribution network, and such. The book is expected to be a useful source of knowledge to the users of GIS who envision its applications in their teaching and research. This easy-to-understand book is surely not the end in itself but a little contribution to toward our understanding of the rich and wonderful subject of GIS