Ken Arroyo Ohori

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Planar partitions are frequently used to model, among others, land cover, cadastral parcels and administrative boundaries. In practice, they are often stored as a set of individual polygons to which attributes are attached (e. g. with the Simple Features paradigm), causing different errors and inconsistencies (e. g. gaps, overlaps and disconnected(More)
The various levels of detail (LODs) of a 3D city model are often stored independently, without links between the representations of the same object, causing inconsistencies, as well as update and maintenance problems. One solution to this problem is to model the LOD as an extra geometric dimension perpendicular to the three spatial ones, resulting in a true(More)
Although the validation of a single GIS polygon can be considered as a solved issue, the repair of an invalid polygon has not received much attention and is still in practice a semi-manual and time-consuming task. We investigate in this paper algorithms to automatically repair a single polygon. Automated repair algorithms can be considered as interpreting(More)
Figure 1: An OBJ dataset (triangles without attributes; left) is converted to CityGML (semantically structured polygons; middle), allowing it to be used to compute the insolation of the roof surfaces. The right model shows the conversion back to OBJ with the insolation value preserved as a material, and an automatically generated colourbar. Abstract We(More)
While there is a growing interest in the use of higher-dimensional (≥4D) digital objects built from complex real-world data, their construction is in practice hampered by a lack of methods and algorithms. We present in this paper a dimension-independent extrusion algorithm for linear geometries using generalised maps. It permits us to create an(More)
Real-world phenomena have traditionally been modelled in 2D/3D GIS. However, powerful insights can be gained by integrating additional non-spatial dimensions, such as time and scale. While this integration to form higher-dimensional objects is theoretically sound, its implementation is problematic since the data models used in GIS are not appropriate. In(More)