vector and object data models

DM-15 - The network model
  • Define the following terms pertaining to a network: Loops, multiple edges, the degree of a vertex, walk, trail, path, cycle, fundamental cycle
  • List definitions of networks that apply to specific applications or industries
  • Create an adjacency table from a sample network
  • Explain how a graph can be written as an adjacency matrix and how this can be used to calculate topological shortest paths in the graph
  • Create an incidence matrix from a sample network
  • Explain how a graph (network) may be directed or undirected
  • Demonstrate how attributes of networks can be used to represent cost, time, distance, or many other measures
  • Demonstrate how the star (or forward star) data structure, which is often employed when digitally storing network information, violates relational normal form, but allows for much faster search and retrieval in network databases
  • Discuss some of the difficulties of applying the standard process-pattern concept to lines and networks
  • Demonstrate how a network is a connected set of edges and vertices
DM-14 - Classic vector data models
  • Illustrate the GBF/DIME data model
  • Describe a Freeman-Huffman chain code
  • Describe the relationship of Freeman-Huffman chain codes to the raster model
  • Discuss the impact of early prototype data models (e.g., POLYVRT and GBF/DIME) on contemporary vector formats
  • Describe the relationship between the GBF/DIME and TIGER structures, the rationale for their design, and their intended primary uses, paying particular attention to the role of graph theory in establishing the difference between GBF/DIME and TIGER files
  • Discuss the advantages and disadvantages of POLYVRT
  • Explain what makes POLYVRT a hierarchical vector data model
DM-13 - The topological model
  • Define terms related to topology (e.g., adjacency, connectivity, overlap, intersect, logical consistency)
  • Describe the integrity constraints of integrated topological models (e.g., POLYVRT)
  • Discuss the historical roots of the Census Bureau’s creation of GBF/DIME as the foundation for the development of topological data structures
  • Explain why integrated topological models have lost favor in commercial GIS software
  • Evaluate the positive and negative impacts of the shift from integrated topological models
  • Discuss the role of graph theory in topological structures
  • Exemplify the concept of planar enforcement (e.g., TIN triangles)
  • Demonstrate how a topological structure can be represented in a relational database structure
  • Explain the advantages and disadvantages of topological data models
  • Illustrate a topological relation
DM-12 - The spaghetti model
  • Identify a widely-used example of the spaghetti model (e.g., AutoCAD DWF, ESRI shapefile)
  • Write a program to read and write a vector data file using a common published format
  • Explain the conditions under which the spaghetti model is useful
  • Explain how the spaghetti data model embodies an object-based view of the world
  • Describe how geometric primitives are implemented in the spaghetti model as independent objects without topology
DM-17 - Object-based spatial databases
  • Discuss the merits of storing geometric data in the same location as attribute data
  • Evaluate the advantages and disadvantages of the object-based data model compared to the layer-based vector data model (topological or spaghetti)
  • Describe the architectures of various object-relational spatial data models, including spatial extensions of DBMS, proprietary object-based data models from GIS vendors, and open-source and standards-based efforts
  • Differentiate between the topological vector data model and spaghetti object data with topological rulebases
  • Write a script (in a GIS, database, or Web environment) to read and write data in an objectbased spatial database
  • Transfer geospatial data from an XML schema to a database
  • Discuss the degree to which various object-relational spatial data models approximate a true object-oriented paradigm, and whether they should
DM-16 - Linear referencing
  • Discuss dynamic segmentation as a process for transforming between linear and planar coordinate systems
  • Construct a data structure to contain point or linear geometry for database record events that are referenced by their position along a linear feature
  • Explain how linear referencing allows attributes to be displayed and analyzed that do not correspond precisely with the underlying segmentation of the network features
  • Describe how linear referencing can eliminate unnecessary segmentation of the underlying network features due to attribute value changes over time
  • Demonstrate how linear referenced locations are often much more intuitive and easy to find in the real world than geographic coordinates
DM-12 - The spaghetti model
  • Identify a widely-used example of the spaghetti model (e.g., AutoCAD DWF, ESRI shapefile)
  • Write a program to read and write a vector data file using a common published format
  • Explain the conditions under which the spaghetti model is useful
  • Explain how the spaghetti data model embodies an object-based view of the world
  • Describe how geometric primitives are implemented in the spaghetti model as independent objects without topology
DM-14 - Classic vector data models
  • Illustrate the GBF/DIME data model
  • Describe a Freeman-Huffman chain code
  • Describe the relationship of Freeman-Huffman chain codes to the raster model
  • Discuss the impact of early prototype data models (e.g., POLYVRT and GBF/DIME) on contemporary vector formats
  • Describe the relationship between the GBF/DIME and TIGER structures, the rationale for their design, and their intended primary uses, paying particular attention to the role of graph theory in establishing the difference between GBF/DIME and TIGER files
  • Discuss the advantages and disadvantages of POLYVRT
  • Explain what makes POLYVRT a hierarchical vector data model
DM-15 - The network model
  • Define the following terms pertaining to a network: Loops, multiple edges, the degree of a vertex, walk, trail, path, cycle, fundamental cycle
  • List definitions of networks that apply to specific applications or industries
  • Create an adjacency table from a sample network
  • Explain how a graph can be written as an adjacency matrix and how this can be used to calculate topological shortest paths in the graph
  • Create an incidence matrix from a sample network
  • Explain how a graph (network) may be directed or undirected
  • Demonstrate how attributes of networks can be used to represent cost, time, distance, or many other measures
  • Demonstrate how the star (or forward star) data structure, which is often employed when digitally storing network information, violates relational normal form, but allows for much faster search and retrieval in network databases
  • Discuss some of the difficulties of applying the standard process-pattern concept to lines and networks
  • Demonstrate how a network is a connected set of edges and vertices
DM-16 - Linear referencing
  • Discuss dynamic segmentation as a process for transforming between linear and planar coordinate systems
  • Construct a data structure to contain point or linear geometry for database record events that are referenced by their position along a linear feature
  • Explain how linear referencing allows attributes to be displayed and analyzed that do not correspond precisely with the underlying segmentation of the network features
  • Describe how linear referencing can eliminate unnecessary segmentation of the underlying network features due to attribute value changes over time
  • Demonstrate how linear referenced locations are often much more intuitive and easy to find in the real world than geographic coordinates

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