Conversions of Relief: on the perception of depth in drawings

Of the many ways in which depth can be intimated in drawings, perspective has undoubtedly been one of the most frequently examined. But there is also an equally rich history associated with other forms of pictorial representation. Alternatives to perspective became particularly significant in the early twentieth century as artists and architects, intent on throwing off the conventions of their predecessors, looked to new ways of depicting depth. In architecture, this tendency was exemplified by Modernism’s preference for parallel projection – most notably axonometric and oblique. The use of these techniques gave architects the opportunity to convey a new and uniquely modern form of spatial expression. At once shallow and yet expansive, a key feature of these drawings was their ability to support perceptual ambiguity. This paper will consider the philosophy and science of vision, out of which these preoccupations emerged. In this context, the nineteenth-century discovery of stereopsis and the invention of the stereoscope will be used to illustrate the way in which attempts to test the limits of spatial perception led to an opening up of visual experience; and provided a definition of visual experience that could encompass the representational ambiguities later exploited by the early twentieth-century avant-garde.

Wind resource mapping using landscape roughness and spatial interpolation methods

Energy saving, reduction of greenhouse gasses and increased use of renewables are key policies to achieve the European 2020 targets. In particular, distributed renewable energy sources, integrated with spatial planning, require novel methods to optimise supply and demand. In contrast with large scale wind turbines, small and medium wind turbines (SMWTs) have a less extensive impact on the use of space and the power system, nevertheless, a significant spatial footprint is still present and the need for good spatial planning is a necessity. To optimise the location of SMWTs, detailed knowledge of the spatial distribution of the average wind speed is essential, hence, in this article, wind measurements and roughness maps were used to create a reliable annual mean wind speed map of Flanders at 10 m above the Earth’s surface. Via roughness transformation, the surface wind speed measurements were converted into meso- and macroscale wind data. The data were further processed by using seven different spatial interpolation methods in order to develop regional wind resource maps. Based on statistical analysis, it was found that the transformation into mesoscale wind, in combination with Simple Kriging, was the most adequate method to create reliable maps for decision-making on optimal production sites for SMWTs in Flanders.