Vector Geographic Information System Research Articles

Local Path Planning of Driverless Car Navigation Based on Jump Point Search Method Under Urban Environment

The Jump Point Search (JPS) algorithm is adopted for local path planning of the driverless car under urban environment, and it is a fast search method applied in path planning. Firstly, a vector Geographic Information System (GIS) map, including Global Positioning System (GPS) position, direction, and lane information, is built for global path planning. Secondly, the GIS map database is utilized in global path planning for the driverless car. Then, the JPS algorithm is adopted to avoid the front obstacle, and to find an optimal local path for the driverless car in the urban environment. Finally, 125 different simulation experiments in the urban environment demonstrate that JPS can search out the optimal and safety path successfully, and meanwhile, it has a lower time complexity compared with the Vector Field Histogram (VFH), the Rapidly Exploring Random Tree (RRT), A*, and the Probabilistic Roadmaps (PRM) algorithms. Furthermore, JPS is validated usefully in the structured urban environment.

Assessing Raster GIS Approximation for Euclidean Shortest Path Routing

AbstractIdentifying a route that avoids obstacles in continuous space is important for infrastructure alignment, robotic travel, and virtual object path planning, among others, because movement through space is not restricted to a predefined road or other network. Vector and raster GIS (geographic information system) solution approaches have been developed to find good/efficient routes. On the vector side, recent solution approaches exploit spatial knowledge and utilize GIS functionality, offering significant computational advantages in finding an optimal solution to this path routing problem. Raster‐based shortest path techniques are widely applied in route planning for wayfinding, corridor alignment, robotics and video gaming to derive an obstacle avoiding path, but represent an approximation approach for solving this problem. This research compares vector and raster approaches for identifying obstacle‐avoiding shortest paths/routes. Empirical assessment is carried out for a number of planning applications, highlighting representational issues, computational requirements and resulting path efficiency.

An agent-integrated irregular automata model of urban land-use dynamics

Urban growth models are useful tools to understand the patterns and processes of urbanization. In recent years, the bottom-up approach of geo-computation, such as cellular automata and agent-based modeling, is commonly used to simulate urban land-use dynamics. This study has developed an integrated model of urban growth called agent-integrated irregular automata (AIIA) by using vector geographic information system environment (i.e. both the data model and operations). The model was tested for the city of San Marcos, Texas to simulate two scenarios of urban growth. Specifically, the study aimed to answer whether incorporating commercial, industrial and institutional agents in the model and using social theories (e.g. utility functions) improves the conventional urban growth modeling. By validating against empirical land-use data, the results suggest that a holistic framework such as AIIA performs better than the existing irregular-automata-based urban growth modeling.

Remote sensing and Geographic Information Systems (GIS) as the applied public health and environmental epidemiology

The public health epidemiology is the study of horizontal and vertical structure of the disease infection state, and health related events and attempt to explain the environmental risk factors (biological, physical, and chemical agents); social settings and factors affecting human contact with these agents, and socioeconomic and environmental condition. GIS has been used to mapping the epidemiological information which includes the burden of disease epidemic transmission, spatial distribution and the determinants of health related states or events in specified population with reference to space and time. Perhaps, remote sensing and GPS has been integrated under the GIS umbrella for disease surveillance, situation analyze and the spatial modelling of disease transmission. The first application of cartography was used in the public health epidemiology for mapping diarrhea disease in London, during 1854 by Jonson Snow, UK physician. However, the applied GIS and remote sensing have not only become essential tool in mapping the both vertical and horizontal epidemiological information, disease surveillance, health monitoring, surveying, sampling design, disease control programs, predicting the disease transmission, and most importantly, incorporated the ge0spatial epidemiological analysis of proximity, similarity, geometry, and cognitive of the disease incidence and the socioeconomic and the ecological variables. It has also become significant decision making tool in heath monitoring, health care management and public health epidemiology. The ERDAS Imagine image processing software and the ARC GIS, Map INFO, Geovariogram+, SPSS are used to mapping, spatial analysis and image processing of the both non-spatial and spatial data. The illustrations are used in the present study based on the data generated from the source of author’s research works and publications, which has relevant information on the public health epidemiological aspects of vector borne disease transmission and GIS for epidemic control and management in India.

Locally weighted linear combination in a vector geographic information system

Weighted linear combination is a multi-criteria decision analysis technique that can be used by decision-makers to select an optimal location from a collection of alternative locations. Its local form takes into account the range of attribute values within a user-defined neighbourhood in accordance with the range-sensitivity principle. This research explores locally weighted linear combination in a vector-based geographic information system. A custom application in ArcGIS 10 allows the user to select a neighbourhood definition from a standard set including contiguity, distance, and k-nearest neighbours, for which local weights are generated. A case study on vulnerability to heat-related illness in Toronto is used to illustrate the technique. The impact of local weighting on the heat vulnerability index is examined using visual analysis of the spatial patterns of heat vulnerability under the global and local approaches, as well as the sensitivity of the local approach to the selected neighbourhood definition. A trade-off analysis of the local weights is also presented. The combination of socio-demographic and environmental determinants in a locally weighted index results in patterns of heat vulnerability that could support targeted hot weather response at a micro-geographic level within urban neighbourhoods.

Meaningful image objects for object-oriented image analysis

Image objects obtained by segmentation usually provide a much more reliable representation of real world objects than individual pixels. However, in regions with high quality spatial information, image analysis should focus on objects of interest rather than artificial image objects. A simple method for applying this object-oriented approach consists of converting existing vector geographic information system (GIS) data into raster objects. A problem with this method is that it may produce image objects with saw-toothed edges which barely match measured objects boundaries. In order to address such a problem, a method for adjusting boundaries of image objects is proposed. The new method uses a vector square grid for pixel representation. Vector-based image objects exhibit boundaries which better reproduce the shape and appearance of GIS objects. The proposed approach was applied to extract geometric and biophysical properties of agricultural plots from remotely sensed imagery. Results suggest that vector-based image objects provide much more accurate values than raster-based image objects.

Using GIS-Based Weighted Linear Combination Analysis and Remote Sensing Techniques to Select Optimum Solid Waste Disposal Sites within Mafraq City, Jordan

Landfill siting was determined within Mafraq City, Jordan, through the integration of geographic information system (GIS), weighted linear combination (WLC) analysis, and remote sensing techniques. Several parameters were collected from various sources in vector and raster GIS formats, and then, used within the GIS-based WLC analysis to select optimum solid waste disposal sites. Namely, urban areas, agricultural lands, access roads, surface aquifers, groundwater table, fault system, water wells, streams, and land slope were considered in this research. Also, the trend of urban expansion within the study area was monitored using the Landsat data of 1989, 1999, and 2009 to support the selection process of disposal sites. It is found that about 84% of the study area was within “most suitable” to “moderately suitable” classes for landfill sites, while the rest of the study area was within “poorly suitable” and “unsuitable” classes. Based on the analysis of Landsat satellite data the urban area was expanded of more than 240% during the last three decades, mainly toward south, and southwest, except the villages near the existing disposal site, where the trend was toward east and northeast. Finally, three sites were suggested as alternatives to the existing disposal site taking into the consideration the environmental, biophysical, and economical variables applied in the GIS-based WLC analysis.

A Map Overlay Error Model Based on Boundary Geometry

An error model for quantifying the magnitudes and variability of errors generated in the areas of polygons during spatial overlay of vector geographic information system layers is presented. Numerical simulation of polygon boundary displacements was used to propagate coordinate errors to spatial overlays. The model departs from most previous error models in that it incorporates spatial dependence of coordinate errors at the scale of the boundary segment. It can be readily adapted to match the scale of error–boundary interactions responsible for error generation on a given overlay. The area of error generated by overlay depends on the sinuosity of polygon boundaries, as well as the magnitude of the coordinate errors on the input layers. Asymmetry in boundary shape has relatively little effect on error generation. Overlay errors are affected by real differences in boundary positions on the input layers, as well as errors in the boundary positions. Real differences between input layers tend to compensate for much of the error generated by coordinate errors. Thus, the area of change measured on an overlay layer produced by the XOR overlay operation will be more accurate if the area of real change depicted on the overlay is large. The model presented here considers these interactions, making it especially useful for estimating errors studies of landscape change over time.

Modelling geographic data with multiple representations

The impact of resolution has been widely studied on raster data, exploring new ways to store and use raster data at different resolution levels. A similar amount of work has not yet been achieved for vector data. The aim of this paper is to propose a framework suitable for vector data for use at different resolution levels. The framework has in fact a wider scope as it has been designed for the general problem of using multiple representations of geographical and thematic data. This problem can be divided into three main issues: data modelling, data matching from different data sets, and data utilization. How can geographical phenomena with several representations be modelled in vector geographic information systems (GIS)? How should different representations be matched to make the data-management systems aware that they all represent the same geographical phenomenon? How can systems supporting multiple representations be used? Answers to these questions have been elaborated as part of the European MurMur project. They are presented here and illustrated using current applications from the French national mapping agency (IGN).

Teaching GIS and Remote Sensing Integration Using Fire Ecology in Longleaf Pine Sandhills

I developed a class assignment that integrates Geographic Information Systems (GIS), remote sensing, and longleaf pine sandhill fire ecology to analyze potential sandhill succession in north central Florida. Students used remotely sensed imagery, vector GIS layers, and raster/vector overlay to complete the assignment. Students found that they could use these two geo-technologies to map and monitor the Normalized Difference Vegetation Index (NDVI) in sandhills and use this information to implement prescribed burns to ward off succession. This assignment taught students not just the tools to integrate GIS and remote sensing but also the importance of using these technologies in tandem to solve real world spatial problems.

Modelling road surface sediment production using a vector geographic information system

Field investigations indicate that unpaved roads are the largest sediment source on St John, US Virgin Islands. Crosssectional measurements of eroded road surfaces were used to establish an empirical relationship to predict annual road surface erosion as a function of road gradient and contributing drainage area. A model (ROADMOD) for estimating and mapping average annual sediment production from a road network was developed by combining this empirical relationship with a series of network algorithms to analyse road data stored in a vector geographic information system. ROADMOD was used to estimate road surface erosion in two St John catchments with very different road densities but similar land cover, topography and soils. Unpaved roads were found to increase sediment production in the more densely roaded catchment by a factor of three to eight, and in the less-roaded catchment by a factor of 1.3-2.0. Turbidity measurements in the receiving bays of these two catchments are consistent with model predictions and observed sediment delivery processes. Although this model was developed specifically for St John, it can easily be adapted to other locations by substituting a locally derived predictive equation for road erosion. Model assumptions, limitations and potential improvements are discussed. @ 1998 John Wiley & Sons, Ltd.

Landscape context of rural residential development in southeastern Wisconsin (USA)

Private on-site sewage systems serve residential development in rural landscapes throughout the United States. In the State of Wisconsin, three major types of private sewage systems facilitate residential development on sites that span gradients in slope, soil permeability, depth to bedrock, and depth to water-table. Conventionalsoil-absorption sewage treatment systems are constructed on sites with minimal physiographic constraints; more highly engineered alternative sewage treatment systems are installed on sites with moderate to severe constraints; holding tanks provide no on-site sewage treatment and are employed on sites with the most severe physiographic limitations. An environmental impact statement (EIS), prepared in 1979 on the proposed widespread use of alternative private sewage systems, suggested that alternative systems might facilitate in-fill development on poor sites near existing cities and lead to compact, higher density development patterns. The research reported in this paper tested the validity of this EIS scenario by comparing development patterns associated with a sample of conventional systems, alternative systems, and holding tanks installed during the 1980s in Ozaukee County, Wisconsin. Land use data, soils data, and other site attribute data were assembled and analyzed in a vector geographic information system (GIS). Because each type of private sewage system has a unique set of siting criteria, the three sets of sampled systems are located in significantly different physiographic regions within the County. Collectively, installations of all three systems facilitated scattered residential development throughout the rural landscape. This development consists of relatively small residential patches dispersed within an agricultural matrix. Wastewater management technology, if not constrained by public policies or other socioeconomic factors, can be an important anthropogenic factor influencing both the process and pattern of landscape change.

Accessibility in the European Union: the impact of the trans-European road network

The aim of this paper is to assess the impact of the future Trans-European Road Network as far as accessibility is concerned. Accessibility analysis and presentation of results is undertaken using a vector geographic information system (GIS). In accordance with the results of the study, the new planned links appreciably modify levels of accessibility to economic activity centres, thus reducing distances and bringing the peripheral regions closer to the central ones. In accordance with the analyses carried out, the benefits of these new infrastructures will affect the whole of the territory of the European Union, albeit particularly so in the peripheral regions.

Exact Computational Methods for Calculating Distances Between Objects in a Cartographic Database

Most existing spatial analytic techniques use a simplified, point-based representation of spatial objects. This facilitates tractability of the standard computational procedures for many spatial measures, for example, distances between spatial objects. The increasing spatial data handling and manipulation capabilities of geographic information systems (GIS), however, allow a re-examination of fundamental representations and measures in spatial analysis. This article develops exact computational procedures for calculating the average, minimum, and maximum distances between pairings of the three geometric primitives (points, lines, and polygons) when these objects are stored in the vector GIS data model. These procedures are “exact” in the sense that they are completely accurate, subject to the database representation. This article also provides example results from average distance calculations for a generic spatial database.

A parallel intersection algorithm for vector polygon overlay

A parallel intersection algorithm for speeding the creation of a composite network of polygons whose identities relate to the original polygons from which they are formed in vector geographic information systems (ISs) is described. The algorithm reduces unnecessary intersection checking, especially when polygon density is high. Single-stream and multiple-stream versions of the algorithm are discussed. Experimental results illustrating the overall performance of the parallel algorithm are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Computer cartography for GIS: An object-oriented view on the display transformation

Geographic Information Systems (GISs) are widely used tools for the collection, management, and display—or visualization—of many types of data that describe space. Visualization of spatial data has been the domain of expertise of cartographers and elaborate recommendations for best rendering of spatial data exist. Unfortunately, this body of knowledge is not cast yet into a formalization and thus is not accessible immediately for programming GIS software. A particular problem is the description of the rendering parameters for complex spatial objects. This paper presents a method for describing the set of individual geometric objects parts to which different rendering parameters can be assigned. The geometric data model uses the concepts of boundary and interior, and their specializations returning objects of particular dimensions. It is applicable equally to both raster and vector data, and, therefore, a contribution to the integration of vector and taster GIS. The rendering parameters are based upon Bertin's “visual variables.” Abbreviated class definitions in C++ are included as a method to describe formally the concepts treated.