ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
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Articles | Volume IV-2/W1
https://doi.org/10.5194/isprs-annals-IV-2-W1-155-2016
https://doi.org/10.5194/isprs-annals-IV-2-W1-155-2016
05 Oct 2016
 | 05 Oct 2016

DEFINING SIMPLE nD OPERATIONS BASED ON PRISMATIC nD OBJECTS

K. Arroyo Ohori, H. Ledoux, and J. Stoter

Keywords: nD GIS, prismatic polytopes, extrusion

Abstract. An alternative to the traditional approaches to model separately 2D/3D space, time, scale and other parametrisable characteristics in GIS lies in the higher-dimensional modelling of geographic information, in which a chosen set of non-spatial characteristics, e.g. time and scale, are modelled as extra geometric dimensions perpendicular to the spatial ones, thus creating a higher-dimensional model. While higher-dimensional models are undoubtedly powerful, they are also hard to create and manipulate due to our lack of an intuitive understanding in dimensions higher than three. As a solution to this problem, this paper proposes a methodology that makes nD object generation easier by splitting the creation and manipulation process into three steps: (i) constructing simple nD objects based on nD prismatic polytopes – analogous to prisms in 3D –, (ii) defining simple modification operations at the vertex level, and (iii) simple postprocessing to fix errors introduced in the model. As a use case, we show how two sets of operations can be defined and implemented in a dimension-independent manner using this methodology: the most common transformations (i.e. translation, scaling and rotation) and the collapse of objects. The nD objects generated in this manner can then be used as a basis for an nD GIS.