عنوان مقاله [English]
Today, ubiquitous Geospatial Information Systems (GIS) has been growing to become the recent generation of GIS. In this generation of GIS, servicing capabilities to any user, at any time, in any location, using any devices, andin any conditions, are provided. Advances in Information Technology (IT)industry have led to the advent of low-cost threedimensional data acquisition technologies (e.g. Microsoft Kinect) that changesthe approaches of current generation of GIS. One of theimportant matters in different generation of GIS is 3D spatialrelations extraction. 3D topological extraction used more in GIS, isdone based on the data models in different generations ofGIS. There are some deficiencies and limitations in current datamodels such as the lack of high interoperability between the userand the environment, lack of visualizing 3D objects relationships witheach other and inconsistency between 3D objects and their primitives,while in ubiquitous generation of GIS by using different sensorsand infrastructures in the environment, these deficiencies are improved. Inthis article, for extracting 3D topological relations in current GISdata models, the methodology of object-oriented procedure and simulationof different objects like sphere and pyramid are done. Bythe way, for the ubiquitous generation of GIS, by usingsmart Kinect sensor, extraction of 3D topological relations is donefor a building prototype. Information Technology (IT) has faced achange in its earliest style of merely making an interactionbetween the users and the environment within a computer. Nowadays, a new era has arrived at which people can communicatewith their environment through embedded sensors on the basis ofubiquitous computing. With the advent of novel technologies of threedimensional information acquisition from the environment, a revolution in theubiquitous computing has occurred which remarkably broadens its capabilities. Oneof these technologies is the use of Microsoft Kinect smartsensor to acquire the depth information in any location andat any time. One of the requirements of Ubiquitous GISis the use of these sensors capabilities in the extractionof spatial relations that empower us with some spatial analysis. The purpose of this article is the comparison of approachesto extracting 3D topological relations based on the data modelsused in different generations of GIS. The use of anappropriate spatial data model for ubiquitous computing makes the extractionof spatial relations at any time and in any locationpossible as a service for the users. Topological relations areconsidered an important property of spatial objects, and are fundamentalto spatial analyses and query-based processing. As the informationcollected by Kinect is in the form of 3D pointclouds, the extraction of three dimensional topological relations is feasible. The spatial analyses describe the topological relations based on somepredefined models which are generated at the same time withthe process of modeling the objects. In this study, basedon a ubiquitous data model and using Kinect as asensor utilized in ubiquitous computing to enhance the interactivity betweenusers and the environment and to acquire 3D information andto extract topological relations. The proposed data model, termed UbiquitousGIS Data Model (UGDM), is able to support various spatialrelations in a metric or non-metric manner. UGDM wellsupports various spatial relations, including directional, distance-based, projection, andtopological relations. The extraction of eight topological relations via differentsensors is among the capabilities of this data model. Theresults of this article for provided data indicate the differencebetween the generations of GIS to extract topological relations, andmore interactions between user and environment in ubiquitous generation ofGIS by different sensors. The extraction of spatial relations betweenobjects provides us with substantial information about their surrounding environment. Directional, distance based and also topological relations are some instancesof spatial relations. The used methodology in this paper accordingto the ubiquitous GIS generation starts with the acquisition ofinformation in the form of point clouds. Then topological informationlike algebraic topology and point set topology are extracted. Providinga ubiquitous data model for extracting 3D topological relations basedon different sensors and infrastructure enhances the interaction between theuser and the environment. This capability in the presented datamodel shows the lack of interoperability in the current datamodels. Providing a language for presented data model in thisarticle is the paper future goal.
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