Geographic data are closely related to both spatial and temporal domains. Geographic information systems (GIS) can capture, manage, analyze, and display spatial data. However, they are not suitable for handling temporal data. Rapid developments of data collection and location-aware technologies stimulate the interests of obtaining useful information from the historical data. Researchers have been working to build various spatio-temporal data models to support spatio-temporal query. Nevertheless, the existing models exhibit weaknesses in various aspects. For instance, the snapshot model is plagued with data redundancy and the event-based spatio-temporal data model (ESTDM) is limited to raster dataset. This study reviews existing spatio-temporal data models in order to design an object-oriented space-time GIS data model that makes additional contributions to processing spatio-temporal data. A binary large object (BLOB) data type, labeled Space-Time BLOB, is added to ArcGIS geodatabase data model to store instantiated space-time objects. A Space-Time BLOB is associated with an array that contains the spatial and temporal information for an object at different time points and time intervals. This study also implements a space-time GIS prototype system, along with a set of spatio-temporal query functions, based on the proposed space-time GIS data model.

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This paper aims to explore the perceptual recognition of topographical building patterns from real-world OpenStreetMap data on virtual globes. An implementation was developed in which all geographical and contextual information was layered and, for the purpose of this study, what solely remained were building patterns as viewed from above. This was developed as a module for the planetarium visualization software Uniview. The aim was to determine how cities with different building patterns were perceived by participants in terms of size, scale, and building density. This was measured as the comparative difference between city pairs, that is, how much they differed in the percentage of the area that they covered. Two quantitative studies were conducted, one smaller controlled study with 19 participants and one larger online crowd-sourced study with 72 participants. The results show that participants are generally able to discern building patterns when the comparative difference is greater than a certain critical threshold. This critical threshold was determined to be at approximately 0.5% for both studies and for accuracy levels above 60%. Thus it was concluded that below this critical threshold users should be provided with visual feedback or other means of identifiers in order to allow for definite recognition, depending on what kind of information a certain type of visualization is trying to convey. / Den här rapporten avser att utforska den perpetuella igenkänningen av topografiska byggnadsmönster genom att använda geografisk data från OpenStreetMap som avbildas på virtuella sfärer. En implementation utvecklades där geografisk data samt kontextuell information ordnades i överlappande lager som filtrerades, och där endast byggnadsmönster sett från ovan kvarstod. Denna modul utvecklades för Uniview som är en mjukvara för visualisering i planetarier. Målet var att avgöra hur deltagare uppfattade städer med olika byggnadsmönster med hänsyn till storlek, skala, samt byggnadsdensitet. Detta mättes genom den procentuella skillnaden mellan städer, dvs. skillnaden i procent för varje stads geografiska utsträckning. Två kvantitativa studier utfördes, en mindre kontrollerad studie med 19 deltagare samt en större nätbaserad studie med 72 deltagare. Resultatet visar att deltagare generellt kunde bedöma den procentuella skillnaden i byggnadsmönster upp till en viss kritisk gräns. Denna kritiska gräns fastställdes till runt 0.5% för båda studier och för noggrannhetsnivåer över 60%. Slutsatsen från detta är att användare bör ges visuella indikatorer för nivåer under denna kritiska gräns för att säkerställa definitiv igenkänning beroende på vilken information som skall förmedlas i en viss typ av visualisering.