Selecting an Appropriate Map Projection

Given the number of projection characteristics, equation parameters, and projection properties that were discussed in Chapter 8, choosing a projection for a given map purpose can be a challenging task. Often, there is no single projection that is the “best” choice for a given map purpose. Instead, the selection process should be thought of as a compromise between desired projection characteristics and properties that meet the needs of a given map purpose. Various authors have developed projection selection guidelines that assist in choosing a projection. These guidelines vary in detail and usefulness. One detailed guideline, developed by John Snyder, presents a hierarchical decision tree-like structure where answers to individual prompts guide the user along a pathway ultimately leading to a suggested projection. Prompts associated with Snyder&s;s guideline, for example, ask the user to consider the geographic area to be mapped, projection properties, and projection characteristics. The chapter explores Snyder&s;s guideline to illustrate the projection selection process for five example map purposes. Using these example map purposes helps illuminate the decisions made at critical points of the selection process and how those decisions impact the final recommended projection, map appearance, and initial map purpose. These five map purposes also illustrate the role that cartographic symbolization methods play in selecting a projection and the projection&s;s impact on overall map design.

Algorithm · Cartography · Geography · Projection (relational algebra) · Artificial Intelligence · Computer Science · Geographic Information Systems Studies