Authors: Fritz Kessler*, Pennsylvania State University - State College, PA
Topics: Cartography, Geographic Information Science and Systems
Keywords: map projection, cartography, GIS, geographic education
Session Type: Paper
Presentation File: No File Uploaded
Many decisions are involved when making a map. One challenging decision involves selecting an appropriate map projection. This challenge rests from the fact that map projections have many parameters and characteristics that need to be considered during the selection process. Added to this complexity are the anticipated tasks that map readers may perform such as visual comparisons, making estimations, and performing measurements. Existing map projection selection guidelines largely provide basic instructions (e.g. thematic maps require equal area projections) which offer little guidance on how to actually select, for example, a specific equal area projection. Generally speaking, selecting an appropriate map projection involves balancing compromises and trade-offs that are not readily discussed in the literature. Moreover, map makers usually lack specific map projection knowledge to understand how to deal with these compromises and trade-offs. To address these shortcomings, we wrote “Working with Projections” to present a new approach to address the challenges that map makers face when selecting a map projection. We frame our projection selection process according to four tenets. First, the map maker is familiar with the typology of their spatial data (e.g., continuous and smooth). Second, the chosen symbolization method is matched to the typology of the spatial data (e.g., choropleth symbolization represents continuous and abrupt spatial data). Third, the map maker successfully anticipates the intended map use tasks at a given geographic scale. Fourth, map maker considers map design as a variable in the map projection selection process.