An interactive tool for teaching map projections

Map projections are one of the fundamental concepts of geographic information science and cartography. An understanding of the different variants and properties is critical when creating maps or carrying out geospatial analyses. To support learning about map projections, we present an online tool that allows to interactively explore the construction process of map projections. A central 3D view shows the three main building blocks for perspective map projections: the globe, the projection surface (cone, cylinder, plane) and the projection center. Interactively adjusting these objects allows to create a multitude of arrangements forming the basis for common map projections. Further insights can be gained by adding supplementary information, such as projection lines and Tissot’s indicatrices. Once all objects have been arranged in a desired way, the projection surface can be unrolled to form the final flat map. Currently, the tool is limited to visualize the construction of true perspective map projections. In the future, prime concerns are to increase the genericity of the application to support more map projections and to integrate it into the GITTA (Geographic Information Technology Training Alliance) platform.