tessellation data models

DM-06 - Grid representations
  • Explain how grid representations embody the field-based view
  • Differentiate among a lattice, a tessellation, and a grid
  • Explain how terrain elevation can be represented by a regular tessellation and by an irregular tessellation
  • Identify the national framework datasets based on a grid model
DM-10 - The Triangulated Irregular Network (TIN) model
  • Describe how to generate a unique TIN solution using Delaunay triangulation
  • Describe the architecture of the TIN model
  • Construct a TIN manually from a set of spot elevations
  • Delineate a set of break lines that improve the accuracy of a TIN
  • Describe the conditions under which a TIN might be more practical than GRID
  • Demonstrate the use of the TIN model for different statistical surfaces (e.g., terrain elevation, population density, disease incidence) in a GIS software application
DM-09 - The hexagonal model
  • Illustrate the hexagonal model
  • Explain the limitations of the grid model compared to the hexagonal model
  • Exemplify the uses (past and potential) of the hexagonal model
DM-11 - Hierarchical data models
  • Illustrate the quadtree model
  • Describe the advantages and disadvantages of the quadtree model for geographic database representation and modeling
  • Describe alternatives to quadtrees for representing hierarchical tessellations (e.g., hextrees, rtrees, pyramids)
  • Explain how quadtrees and other hierarchical tessellations can be used to index large volumes of raster or vector data
  • Implement a format for encoding quadtrees in a data file
DM-10 - The Triangulated Irregular Network (TIN) model
  • Describe how to generate a unique TIN solution using Delaunay triangulation
  • Describe the architecture of the TIN model
  • Construct a TIN manually from a set of spot elevations
  • Delineate a set of break lines that improve the accuracy of a TIN
  • Describe the conditions under which a TIN might be more practical than GRID
  • Demonstrate the use of the TIN model for different statistical surfaces (e.g., terrain elevation, population density, disease incidence) in a GIS software application
DM-09 - The hexagonal model
  • Illustrate the hexagonal model
  • Explain the limitations of the grid model compared to the hexagonal model
  • Exemplify the uses (past and potential) of the hexagonal model
DM-08 - Grid compression methods
  • Illustrate the existing methods for compressing gridded data (e.g., run length encoding, Lempel-Ziv, wavelets)
  • Explain the advantage of wavelet compression
  • Evaluate the relative merits of grid compression methods for storage
  • Differentiate between lossy and lossless compression methods
DM-07 - The raster model
  • Define basic terms used in the raster data model (e.g., cell, row, column, value)
  • Write a program to read and write a raster data file
  • Compare and contrast the raster with other types of regular tessellations for geographic data analysis
  • Compare and contrast the raster with other types of regular tessellations for geographic data storage
  • Interpret the header of a standard raster data file
  • Explain how the raster data model instantiates a grid representation
DM-06 - Grid representations
  • Explain how grid representations embody the field-based view
  • Differentiate among a lattice, a tessellation, and a grid
  • Explain how terrain elevation can be represented by a regular tessellation and by an irregular tessellation
  • Identify the national framework datasets based on a grid model
DM-11 - Hierarchical data models
  • Illustrate the quadtree model
  • Describe the advantages and disadvantages of the quadtree model for geographic database representation and modeling
  • Describe alternatives to quadtrees for representing hierarchical tessellations (e.g., hextrees, rtrees, pyramids)
  • Explain how quadtrees and other hierarchical tessellations can be used to index large volumes of raster or vector data
  • Implement a format for encoding quadtrees in a data file

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