1550915682029_Spatial Databases as Models of Reality.pdf - UNIT 10 SPATIAL DATABASES AS MODELS OF REALITY UNIT 10 SPATIAL DATABASES AS MODELS OF REALITY

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UNIT 10 - SPATIAL DATABASES AS MODELS OF REALITY UNIT 10 - SPATIAL DATABASES AS MODELS OF REALITY Compiled with assistance from Timothy L. Nyerges, University of Washington A. INTRODUCTION Definition Standards B. DATABASE CONTENT AND AN ORGANIZATION'S MISSION Organization mandates Database contents Database design C. FUNDAMENTAL DATABASE ELEMENTS Entity Object Entity types Spatial object type Object classes Attributes Attribute value Database model Layers D. DATABASE DESIGN Steps in database design Desirable database characteristics Issues in database design REFERENCES EXAM AND DISCUSSION QUESTIONS NOTES This begins a three unit section covering some basic principles of spatial databases. As these issues are very fundamental, many of them are introduced here but dealt with in much greater detail in later units. UNIT 10 - SPATIAL DATABASES AS MODELS OF REALITY
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Compiled with assistance from Timothy L. Nyerges, University of Washington A. INTRODUCTION the real world is too complex for our immediate and direct understanding we create "models" of reality that are intended to have some similarity with selected aspects of the real world databases are created from these "models" as a fundamental step in coming to know the nature and status of that reality Definition a spatial database is a collection of spatially referenced data that acts as a model of reality a database is a model of reality in the sense that the database represents a selected set or approximation of phenomena these selected phenomena are deemed important enough to represent in digital form the digital representation might be for some past, present or future time period (or contain some combination of several time periods in an organized fashion) Standards many of the definitions in this Unit have been standardized by the proposed US National Digital Cartographic Standard (DCDSTF, 1988) these standards have been developed to provide a nationally uniform means for portraying and exchanging digital cartographic data these cartographic standards will form part of a larger standard being developed for the digital representation of all earth science information B. DATABASE CONTENT AND AN ORGANIZATION'S MISSION Organization mandates organizations have mandates to perform certain tasks that carry out their missions mandates are the reasons they exist as organizations organizations have different needs for data depending on their mandates and the activities required to carry out these mandates mandates often help identify and define entities of interest, requiring a certain view of the world what might seem at first glance to be the same data need in two different organizations can actually be quite different when we look at a more detailed level e.g. wildlife and forestry departments both need information on vegetation but the detail needed is different Database contents Example: Transportation
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