## 2020 QUARTER 01

##### 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.

##### 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-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
• Illustrate a topological relation
##### 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
##### FC-27 - Thematic accuracy
• Explain the distinction between thematic accuracy, geometric accuracy, and topological fidelity
• Outline the SDTS and ISO TC211 standards for thematic accuracy
• Discuss how measures of spatial autocorrelation may be used to evaluate thematic accuracy
• Describe the component measures and the utility of a misclassification matrix
• Describe the different measurement levels on which thematic accuracy is based
##### AM-86 - Theory of error propagation
• Describe stochastic error models
• Exemplify stochastic error models used in GIScience
##### FC-08 - Time

Time is a fundamental concept in geography and many other disciplines. This article introduces time at three levels. At the philosophical level, the article reviews various notions on the nature of time from early mythology to modern science and reveals the dual nature of reality: external (absolute, physical) and internal (perceived, cognitive). At the analytical level, it introduces the measurement of time, the two frames of temporal reference: calendar time and clock time, and the standard time for use globally. The article continues to discuss time in GIS at the practical level. The GISystem was first created as a “static” computer-based system that stores the present status of a dynamic system. Now, GISystems can track and model the dynamics in geographical phenomena and human-environment interactions. Representations of time in dynamic GISystems adopt three perspectives: discrete time, continuous time and Minkowski’s spacetime, and three representations: ordinal, interval, and cyclical. The appropriate perspective and representation depend on the observed temporal patterns, which can be static, oscillating, chaotic, or stochastic. Recent progress in digital technology brings us opportunities and challenges to collect, manage and analyze spatio-temporal data to advance our understanding of dynamical phenomena.

##### DM-28 - Topological relationships
• Define various terms used to describe topological relationships, such as disjoint, overlap, within, and intersect
• List the possible topological relationships between entities in space (e.g., 9-intersection) and time
• Use methods that analyze topological relationships
• Recognize the contributions of topology (the branch of mathematics) to the study of geographic relationships
• Describe geographic phenomena in terms of their topological relationships in space and time to other phenomena
##### CV-10 - Typography

The selection of appropriate type on maps, far from an arbitrary design decision, is an integral part of establishing the content and tone of the map. Typefaces have personalities, which contribute to the rhetorical message of the map. It is important to understand how to assess typefaces for their personalities, but also to understand which typefaces may be more or less legible in a labeling context. Beyond the choice of typeface, effective map labels will have a visual hierarchy and allow the user to easily associate labels to their features and feature types. The cartographer must understand and modify typographic visual variables to support both the hierarchy and label-feature associations.