Building the Altiplano model

altiplano model 1
Above, the model up to the 12,000ft level. The 12,000ft paper print has been glued to the 12,000ft polystyrene level.

The model has a base size of A1, which is 840mm x 594mm. Before beginning the model, it was necessary to find a map of appropiate size and scale, with contours at regular intervals. The map chosen was the USAF Operational Navigational Chart (ONC) at a scale of 1:1,000,000, purchased from Stanford's Map Shop, Longacre, London. Sheet ONC P-26 covered most of the region but a small part of the sheet above was also necessary. Once the two sheets were joined together, the area chosen was marked out in pencil and the sheets trimmed to a convenient size just slightly larger than the area chosen. This area was then overlayed with a sheet of drafting film and a master drawing prepared onto which were traced all the contours at 1,000ft intervals. From this master drawing, paper prints were then made of the respective contour levels.

It was then necessary to decide a vertical scale for the model. If true to scale at 1:1,000,000, the height to the 12,000ft level of the Altiplano would be only 3.65mm giving little impression of height. Each contour level had to be cut out of polystyrene, so it was convenient to construct the levels up to 13,000 feet using " (6mm) polystyrene. This would give the model from 0 to 12,000 ft a scale of 1/48000 and a height of 3" (72mm) so the western coastline for example had more of the impression of "rising sheer our of the sea to a great height" as per Plato's quotation. For the height of the mountains above 13,000ft a different scale was used. Experimental profiles were made and levels 14,000ft and 15,000ft were cut from 1/8th (3mm) polystyrene. For heights above 15,000ft, instead of cutting out of polystyrene, pins were driven into the model at the respective centres of the mountains and adjusted to height at an appropriate scale, see further below.

For the first level, the paper print of the 1,000ft contour was cut out with a scissors to give the shape of the 1,000ft contour. This paper print was then glued with aerosol spray adhesive to a sheet of quarter-inch polystyrene, then using a heated wire, the shape was cut from the polystyrene. The polystyrene shape was then glued to the board. This was repeated for each of the layers up to 12,000ft gluing each level to the preceeding level and also for the two layers above using one eighth inch polystyrene.

altiplano model 2
Above, the model takes shape with the respective layers of polystyrene.

altiplano model 2
Above, the model begins to take shape. A 12,000ft paper print was glued to the polystyrene in order to show the respective positions of the subsequent layers.

altiplano model 3
Above, the rectangular Altiplano is at a level of 12,000ft and its shape is defined by the 13,000ft contour. A 12,000ft paper print was glued to the polystyrene in order to show the respective positions of the subsequent layers. Various layers up to 16,000ft along with pins marking the heights of individual mountains are shown. For example, volcan Tunupa on the 1:1,000,000 map has a width at the 13,000ft contour (shown above) of 11mm. It has a height of 17,716ft. We wish to insert a pin so that it will have a suitable height on the model to give an impression of a volcano. From the height of 17,716ft we subtract 12,000ft of the level plain leaving a height for the volcano of 5,716ft above the level Altiplano. We draw an experimental scale drawing of a width of 11mm as per the map, and try a vertical height to scale of 1/96,000 to see how it looks, which would give a height of about 18mm above the 12,000ft level plain on the model - result the volcano looks too exagerated in height. We redraw the profile using a vertical scale of 1/192,000 and the height becomes 9mm above the 12,000ft level Altiplano and the volcano comes out looking about right.

altiplano model 4
Above, the model was next covered in a layer of modelling clay

altiplano model 5
Above, the model covered in a layer of modelling clay.

altiplano model coloured
The model is painted in appropriate colours. Various transparant overlays
were also made, for example to show the positions of the salars de Coipasa and Uyuni.

altiplano model in case
Above, The original model was built into a travelling case. In order to make it more durable, the outer surface of the model was covered in polyester resin before being re-painted, the polystyrene interior scooped out and the interior of the model coated in polyester resin reinforced with fibreglass matting and a wooden brace.

south america model
Above, The underside of the lid of the travelling case supported another model, this time of the whole of South America.

J.M. Allen