It is possible to simulate a three-dimensional relief via stacked glass layers. Each glass layer, often consisting of a transparent plastic sheet, corresponds to one elevation level. Several layers stacked vertically can represent a three-dimensional object. All layers together form a transparent block and the features depicted seem to be suspended. The steps originating from the discrete layers cannot be eliminated. In such manner, it is possible to easily create reliefs derived from contour maps by gluing maps on the layers: For each contour level, a map cut along the corresponding contour is glued on a new layer. Instead of using maps it is also possible to draw directly onto the glass.
This technique allows depicting even tiny details like the framework of a latticework bridge as well as caves, mines or tunnels.
This article bases on Terrain models and relief map making. 1956. p.53-62. and Mühle, Helmut. Manuelle Geländemodell-Herstellungsverfahren unter Berücksichtigung des Standes der Technik. 1963. S.44,45,53.
A little pocket relief that could be taken along during a trip facilitated the navigation of people untrained in interpreting maps. Particularly before the circulation of contour maps, a little model of the terrain could help finding one's way in mountainous regions. Carl August Schöll (1810–1878) created such a relief based on a map of 1813 created by Heinrich Keller (1778–1862).
Source Terrain Models