DM-21 - Modeling three-dimensional (3-D) entities

Learning Objectives: 
  • Identify GIS application domains in which true 3-D models of natural phenomena are necessary
  • Illustrate the use of Virtual Reality Modeling Language (VRML) to model landscapes in 3-D
  • Explain how octatrees are the 3-D extension of quadtrees
  • Explain how voxels and stack-unit maps that show the topography of a series of geologic layers¬†might be considered 3-D extensions of field and vector representations respectively
  • Explain how 3-D models can be extended to additional dimensions
  • Explain the use of multi-patching to represent 3-D objects
  • Explain the difficulties in creating true 3-D objects in a vector or raster format
  • Differentiate between 21/2-D representations and true 3-D models