# A Review on Augmented Reality in Education and Geography: State of the Art and Perspectives
## 6 Augmented Reality Sandbox  
Among the various types of AR applications used in geographical education, the AR Sandbox stands out because it is a tactile and visually immersive learning tool. Due to its relevance to topographical modeling and environmental simulations, this application needs its own dedicated section. The isolation of AR Sandbox from other tools happens not only because it is a widespread tool and has unique pedagogical advantages but also because of the substantial differences in how it is implemented and experienced compared to mobile or screen AR systems. Moreover, this focus is also justified by the development of a newly constructed AR Sandbox system by the authors as part of this research effort, called AR Topography. This original prototype, inspired by earlier models such as Illumina Clay and SandScape, was built using accessible hardware, such as the Xbox Kinect sensor and Raspberry Pi, and tailored for an educational environment. Its creation provided direct, practical insights into the strengths and limitations of current systems, observed both in the comparative analysis and future development proposals presented in this section. By combining literature synthesis with first-hand implementation experience, this section offers a more in-depth exploration of AR Sandbox systems in education. Therefore, it is not simply a review of existing literature but also contains added value by original prototyping work and hands-on implementation. As such, the AR Sandbox section serves as a bridge between theoretical applications of AR in geography and their concrete classroom implementations. Even though there are many types of implementations of AR Sandbox, all of them have the same basis: a sandbox that is filled with a material, which can be modeled in any way, and then the topographic map of that formed landform is displayed on top of the material. According to [33], a topographic map is a map that represents in great detail a certain landscape, using color-coded heights, usually ranging from dark blue, representing the lowest point, to white, representing the highest point on the map. It may also have contour lines that are closed curves representing areas on the map, which have the same altitude. Also, the contour lines must be drawn at a 100m difference in altitude. The differences between the versions and implementations of the AR Sandbox can be observed in how the topographic map of the landscape created is displayed, the computation used for the topographic map, and the moldable material used. One of the original AR Sandbox versions is Illuminating Clay [34]. Figure 8 shows a representation of the AR application. The device enables the user to interact with clay (C), which is a moldable material, within the worktable, represented as D. Then, the geometry and thus, the landscape formed by the user, is continuously scanned by using a laser scanner, represented in the figure as B. The scanned model is sent to a computer, which transforms the landscape into a digital elevation model, which is then projected with the aid of a projector (A), on top of the clay. The moldable material chosen was clay, because the authors stated that they wanted to use a material that is tactile, rich, easy to manipulate, and which allows \"freeform landscape manipulations\". For the laser scanning, the authors used a triangulation-based laser scanner, Minolta Vivid-900. The scanner uses a laser sheet to measure the distance from the scanner to the surface. The laser interacts with the object's surface, in this case the clay, and reflects the laser light. Inside the Minolta Vivid-900, there is the laser emitter and the internal camera that captures the laser that is being reflected. Because the angles and positions of the laser emitter and camera are known, the position of every point in the scanned model can be easily computed using trigonometry. Figure 8: Representation of Illuminating Clay.