Browsing by Subject "Geographic information systems"

Now showing 1 - 6 of 6

Open Access
Diffusion of geograpgic information system at municipalities in Istanbul
(Chamber of Mining Engineers of Turkey, 2015-04) Çavur, M.; Özturan, M.; Karaduman, C.; İçli, Abdullah Bera
This study aims to develop a better understanding of diffusion of Geographic Information Systems within municipalities and examines the infrastructure of Istanbul municipalities and whether they are ready for this technology or not. This study uses two research methods: The first one comprises interviews with the experts of GIS in Turkey. The second one comprises questionnaires conducted with Geographic Information Systems - related departments of Istanbul municipalities. Data collected online have been analyzed by using descriptive statistics, reliability tests, Anova and regression to test the hypotheses. One of the findings is that almost half of the municipalities implement Geographic Information Systems without a vision or a plan for the future. Another finding is that Geographic Information Systems is mainly used to perform registration and maintenance functions instead of supporting the decision-making process. Finally, there is an optimistic expectation of municipalities regarding the use of Geographic Information Systems in the future.
Open Access
Fire detection and 3D fire propagation estimation for the protection of cultural heritage areas
(Copernicus GmbH, 2010) Dimitropoulos, K.; Köse, Kıvanç; Grammalidis, N.; Çetin, A. Enis
Beyond taking precautionary measures to avoid a forest fire, early warning and immediate response to a fire breakout are the only ways to avoid great losses and environmental and cultural heritage damages. To this end, this paper aims to present a computer vision based algorithm for wildfire detection and a 3D fire propagation estimation system. The main detection algorithm is composed of four sub-algorithms detecting (i) slow moving objects, (ii) smoke-coloured regions, (iii) rising regions, and (iv) shadow regions. After detecting a wildfire, the main focus should be the estimation of its propagation direction and speed. If the model of the vegetation and other important parameters like wind speed, slope, aspect of the ground surface, etc. are known; the propagation of fire can be estimated. This propagation can then be visualized in any 3D-GIS environment that supports KML files.
Open Access
A GIS ‐ based framework for hazardous materials transport risk assessment
(Wiley-Blackwell Publishing, 2001) Verter, V.; Kara, B. Y.
This article presents a methodology for assessment of the hazardous materials transport risk in a multicommodity, multiple origin – destination setting. The proposed risk assessment methodology was integrated with a Geographical Information System (GIS), which made large‐scale implementation possible. A GIS‐based model of the truck shipments of dangerous goods via the highway network of Quebec and Ontario was developed. Based on the origin and destination of each shipment, the risk associated with the routes that minimize (1) the transport distance, (2) the population exposure, (3) the expected number of people to be evacuated in case of an incident, and (4) the probability of an incident during transportation was evaluated. Using these assessments, a government agency can estimate the impact of alternative policies that could alter the carriers’ route choices. A related issue is the spatial distribution of transport risk, because an unfair distribution is likely to cause public concern. Thus, an analysis of transport risk equity in the provinces of Quebec and Ontario is also provided.
Open Access
Interactive training of advanced classifiers for mining remote sensing image archives
(ACM, 2004) Aksoy, Selim; Koperski, K.; Tusk, C.; Marchisio G.
Advances in satellite technology and availability of down-loaded images constantly increase the sizes of remote sensing image archives. Automatic content extraction, classification and content-based retrieval have become highly desired goals for the development of intelligent remote sensing databases. The common approach for mining these databases uses rules created by analysts. However, incorporating GIS information and human expert knowledge with digital image processing improves remote sensing image analysis. We developed a system that uses decision tree classifiers for interactive learning of land cover models and mining of image archives. Decision trees provide a promising solution for this problem because they can operate on both numerical (continuous) and categorical (discrete) data sources, and they do not require any assumptions about neither the distributions nor the independence of attribute values. This is especially important for the fusion of measurements from different sources like spectral data, DEM data and other ancillary GIS data. Furthermore, using surrogate splits provides the capability of dealing with missing data during both training and classification, and enables handling instrument malfunctions or the cases where one or more measurements do not exist for some locations. Quantitative and qualitative performance evaluation showed that decision trees provide powerful tools for modeling both pixel and region contents of images and mining of remote sensing image archives.
Open Access
KiMPA: A kinematics-based method for polygon approximation
(Springer, Berlin, Heidelberg, 2002) Şaykol, Ediz; Gülesir, Gürcan; Güdükbay, Uğur; Ulusoy, Özgür
In different types of information systems, such as multimedia information systems and geographic information systems, object-based information is represented via polygons corresponding to the boundaries of object regions. In many applications, the polygons have large number of vertices and edges, thus a way of representing the polygons with less number of vertices and edges is developed. This approach, called polygon approximation, or polygon simplification, is basically motivated with the difficulties faced in processing polygons with large number of vertices. Besides, large memory usage and disk requirements, and the possibility of having relatively more noise can also be considered as the reasons for polygon simplification. In this paper, a kinematics-based method for polygon approximation is proposed. The vertices of polygons are simplified according to the velocities and accelerations of the vertices with respect to the centroid of the polygon. Another property of the proposed method is that the user may set the number of vertices to be in the approximated polygon, and may hierarchically simplify the output. The approximation method is demonstrated through the experiments based on a set of polygonal objects. © Springer-Verlag Berlin Heidelberg 2002.
Open Access
Selective replicated declustering for arbitrary queries
(Springer, 2009-08) Oktay, K. Yasin; Türk, Ata; Aykanat, Cevdet
Data declustering is used to minimize query response times in data intensive applications. In this technique, query retrieval process is parallelized by distributing the data among several disks and it is useful in applications such as geographic information systems that access huge amounts of data. Declustering with replication is an extension of declustering with possible data replicas in the system. Many replicated declustering schemes have been proposed. Most of these schemes generate two or more copies of all data items. However, some applications have very large data sizes and even having two copies of all data items may not be feasible. In such systems selective replication is a necessity. Furthermore, existing replication schemes are not designed to utilize query distribution information if such information is available. In this study we propose a replicated declustering scheme that decides both on the data items to be replicated and the assignment of all data items to disks when there is limited replication capacity. We make use of available query information in order to decide replication and partitioning of the data and try to optimize aggregate parallel response time. We propose and implement a Fiduccia-Mattheyses-like iterative improvement algorithm to obtain a two-way replicated declustering and use this algorithm in a recursive framework to generate a multi-way replicated declustering. Experiments conducted with arbitrary queries on real datasets show that, especially for low replication constraints, the proposed scheme yields better performance results compared to existing replicated declustering schemes. © 2009 Springer.