vector data - Vector Data Model Fall 2007 Data Model An...

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Vector Data Model Fall 2007
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Data Model An abstraction of the real world Incorporates relevant properties to specific application Defines objects/entities and relationships
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Vector Data Model Abstraction of of real world represented by coordinates Features are in discrete units Abstraction units: points, lines, and polygons May or may not have topology
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Topology: spatial relationships in vector data models Topological relationships: adjacency (what adjoins what) containment (what encloses what) and proximity (how close something is to something else).
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Vector Data Models Two Parts Spatial: manages spatial data Attributes: manages thematic data. Two Types: Georelational vector data Object oriented vector data
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Vector Data Representation Points, lines (polylines), polygons http://www.sli.unimelb.edu.au/gisweb/GISModule/GIST_Vector.htm
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Vector Data Model (Structure and Data Storage) 1. Spaghetti model – simple, no topology, duplication
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2. Vertex Dictionary – no duplication, no topology
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3. Dual Independent Map Encoding (DIME) format Has directional codes (from – to)
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4. Arc Structure
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vector data - Vector Data Model Fall 2007 Data Model An...

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