Data Models in Commercial GIS Systems E. Hoel, page CSCI 5715 – Fall /14/2014 Sameera Shah Shyam Sundar Somasundaram
Relevance Week 2 - Spatial Concepts and Data Models ( Ch. 2) 2
Categorization Commercial GIS Data ModelsRasterVectorSpaghettiTopologyNetworkDirectedUndirectedDEM Raster DEM TIN (Vector) 3
Raster Model Stores data in matrix form Useful for data varying continuously e.g. aerial photograph Single images Raster Catalog Collection of rasters Source: 4
Vector Model (1/4) Co-ordinate based data model Useful for storing data that has discrete boundaries Classified into further subtypes Spaghetti Network Topological 5
Spaghetti Model (2/4) Simple Data Model or Spaghetti Plot Geometric representations have no explicit relationship E.g. Hurricane model Source: 6
Network Model (3/4) One dimensional collection of point (junction) and line(edges) features Directed e.g. water flow modeling Hydrologic networks Utility networks Undirected e.g. transportation network Source: 7
Topology Models (4/4) Control geometric relationships Collection of nodes, arcs, faces and their inter relationships E.g. United States Census geographic data Source: Point features (traffic signs), shown as dark circles: S1, S2, S3, and S4 Linear features (roads or streets), shown as dashed lines: R1, R2, R3, and R4 Area features (land parcels), shown as rectangles: P1, P2, P3, P4, and P5 8
Digital Elevation Model (DEM) Represent the surface topography of the earth Built from remote sensing data or survey methods E.g. perform line-of-sight for cell phone Classified based on type of source data as: Raster DEM TIN DEM 9 Source:
TIN DEM A.k.a Vector based surface model Contiguous non – overlapping triangles Nodes, edges, triangles Facilitates surface modeling 10 Source
Future Directions Available data for specific times /dates Augment existing data models to support temporal data 11
References Data Models in Commercial GIS Systems, E. Hoel, page Spatial Databases: A Tour, S. Shekhar and S. Chawla, Prentice Hall,
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