Beyond Terrain Shapes: Exercises Using 3-D Printed Models for Introductory Geology and Planetary Science Courses

Many students in geoscience courses struggle with exercises using spatial datasets due to inexperience and difficulty with visual interpretation. The availability of lower cost 3-D printers provides an opportunity to assist students by providing tactile and interactive representations of these data.

One of the most common spatial datasets used in geoscience is elevation, often presented in topographic maps and/or digital elevation models (DEMs) that may be unfamiliar to many, especially in introductory courses. In addition to aiding in translation of 2-D map/image information to a third dimension, 3-D printed models provide additional tactile data about slope and surface roughness, and can aid in presenting concepts that may be difficult to visualize (e.g. vertical exaggeration).

An example where 3-D models provide additional tactile information is the global topography of Mars collected by spacecraft (Mars Global Surveyor and Mars Express). The northern and southern hemispheres of Mars differ in average elevation and in the number of impact craters. Through an exercise that explores this "hemispheric dichotomy" via 3-D prints along with grayscale DEMs, students are able to observe the difference in elevation and to observe by feel the difference in crater density. The sparsely cratered northern hemisphere feels smooth in 3-D prints, while the cratered southern highlands is rough.

We often ask students to observe correlations in related datasets using side-by-side graphs or composite images. 3-D models with one dataset represented on each side can provide an additional tactile input: for example, double-sided models where one side represents topography and the other local gravity anomalies allows students to feel for places where the two datasets are correlated based on the thickness of the model. These models are also durable and lightweight, making them ideal additions to material presented during field trips.