Status: this preprint is open for discussion and under review for Geoscience Communication (GC).
GC Insights: Choosing the right map projection, and what it means for scale bars and north arrows
Dominic Royé
Abstract. Map projection choice is usually left to software defaults, yet it determines whether spatial patterns are shown faithfully or systematically distorted. Because every projection trades area, shape, distance, and direction differently, the validity of two common map elements, the scale bar and the north arrow, depends entirely on the projection chosen. A survey of 299 maps drawn at random from a frame of 27 geoscience journals finds that 1.7 % name their projection, 44 % give no way to determine it, and only 16 % draw a graticule, the one device that shows the geometry rather than approximating it. This Insight argues that projection should be a deliberate, purpose-driven choice, and that journals should require authors to declare the coordinate reference system in figure captions.
Received: 14 Jul 2026 – Discussion started: 27 Aug 2026
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Scientists often keep a map's default projection without question, even though every projection changes how sizes, shapes, and distances appear. Scale bars and direction arrows are only accurate under certain projections, so a poor choice can make them misleading. Motivated by how often this goes unnoticed in published research, this paper argues that projections should be chosen deliberately and stated in each figure, so readers can trust what a map is showing.
Scientists often keep a map's default projection without question, even though every projection...
