2020 QUARTER 03

A B C D E F G H I J K L M N O P R S T U V W
CV-14 - Terrain Representation

Terrain representation is the manner by which elevation data are visualized. Data are typically stored as 2.5D grid representations, including digital elevation models (DEMs) in raster format and triangulated irregular networks (TINs). These models facilitate terrain representations such as contours, shaded relief, spot heights, and hypsometric tints, as well as automate calculations of surface derivatives such as slope, aspect, and curvature. 3D effects have viewing directions perpendicular (plan), parallel (profile), or panoramic (oblique view) to the elevation’s vertical datum plane. Recent research has focused on automating, stylizing, and enhancing terrain representations. From the user’s perspective, representations of elevation are measurable or provide a 3D visual effect, with much overlap between the two. The ones a user can measure or derive include contours, hypsometric tinting, slope, aspect, and curvature. Other representations focus on 3D effect and may include aesthetic considerations, such as hachures, relief shading, physiographic maps, block diagrams, rock drawings, and scree patterns. Relief shading creates the 3D effect using the surface normal and illumination vectors with the Lambertian assumption. Non-plan profile or panoramic views are often enhanced by vertical exaggeration. Cartographers combine techniques to mimic or create mapping styles, such as the Swiss-style.

DM-49 - Tessellated referencing systems
  • Explain the concept “quadtree”
  • Describe the octahedral quarternary triangulated mesh georeferencing system proposed by Dutton
  • Discuss the advantages of hierarchical coordinates relative to geographic and plane coordinate systems
KE-29 - The geospatial community
  • Describe possible benefits to an organization by participating in a given society that is related to GIS&T
  • Discuss the value or effect of participation in societies, conferences, and informal communities to entities managing enterprise GIS
  • Identify conferences that are related to GIS&T
KE-30 - The geospatial industry
  • Assess the involvement of non-GIS companies (e.g., Microsoft, Google) in the geospatial industry
  • Describe three applications of geospatial technology for different workforce domains (e.g., first responders, forestry, water resource management, facilities management)
  • Explain why software products sold by U.S. companies may predominate in foreign markets, including Europe and Australia
  • Describe the U.S. geospatial industry including vendors, software, hardware and data
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
GS-01 - The legal regime
  • Discuss ways in which the geospatial profession is regulated under the U.S. legal regime
  • Compare and contrast the relationship of the geospatial profession and the U.S. legal regime with similar relationships in other countries
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
FC-20 - The power of maps
  • Describe how maps such as topographic maps are produced within certain relations of power and knowledge
  • Discuss how the choices used in the design of a road map will influence the experience visitors may have of the area
  • Explain how legal issues impact the design and content of such special purpose maps as subdivision plans, nautical charts, and cadastral maps
  • Exemplify maps that illustrate the provocative, propagandistic, political, and persuasive nature of maps and geospatial data
  • Demonstrate how different methods of data classification for a single dataset can produce maps that will be interpreted very differently by the user
  • Deconstruct the silences (feature omissions) on a map of a personally well known area
  • Construct two maps about a conflict or war producing one supportive of each side’s viewpoint
KE-01 - The process of GIS&T design
  • Describe the major approaches to the design of geospatial systems
  • Analyze past cases to identify best practices of design and implementation
  • Compare and contrast the relative merits of the use-case driven and architecture-centric design processes
DM-07 - The Raster Data Model

The raster data model is a widely used method of storing geographic data. The model most commonly takes the form of a grid-like structure that holds values at regularly spaced intervals over the extent of the raster. Rasters are especially well suited for storing continuous data such as temperature and elevation values, but can hold discrete and categorical data such as land use as well.  The resolution of a raster is given in linear units (e.g., meters) or angular units (e.g., one arc second) and defines the extent along one side of the grid cell. High (or fine) resolution rasters have comparatively closer spacing and more grid cells than low (or coarse) resolution rasters, and require relatively more memory to store. Active research in the domain is oriented toward improving compression schemes and implementation for alternative cell shapes (such as hexagons), and better supporting multi-resolution raster storage and analysis functions.

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