Spatial relation
A spatial relation (also spatial relation to) indicates the position at which an object is a reference object in space relative.
overview
Types of spatial relations are
- topological relations (near, at, on),
- Directional relations (in the north, south, east, west, in front of, behind, next to, to the right of).
The object to be localized is normally significantly smaller than the reference object , because otherwise it would not make sense to specify the location using the reference object. For example, nobody would describe the location of a cathedral by being behind a bicycle. The object to be localized is therefore often approximated by a point, provided it is not located directly next to the reference object. The reference object, on the other hand, is often approximated by a cuboid or polygon .
Object orientation
If the applicability for a certain directional relation between different objects is to be calculated, the front side of the reference object may have to be determined first, depending on the selected relation. A distinction is made here between intrinsic and extrinsic orientation. Intrinsic orientation exists when the orientation is already given by the object itself, e.g. B. in a cabinet, the front is determined by its doors. One speaks of extrinsic orientation when the object itself does not have a front (e.g. a table), but a front is induced onto it by its surroundings. For example, when a table is against a wall, the side of the table facing away from the wall is called the front. After the front of the object has been determined, a direction vector can be constructed that characterizes the corresponding spatial relation.
Calculation algorithm
An algorithm that is often used for calculating directional relationships is to determine a connection vector between the object to be localized and the point of the reference object which is closest to the object to be localized. The degree of applicability for a specific directional relation can then be specified on the basis of the angle with respect to the directional vector characterizing the spatial relation.
Publications
- Zimmer, Hubert D. and Speiser, Harry R. and Baus, Joerg and Blocher, Anselm and Stopp, Eva: " The Use of Locative Expressions in Dependence of the Spatial Relation between Target and Reference Object in Two-Dimensional Layouts" , Saarbrücken University 1998
- Ferguson, RW, & Forbus, KD .: " GeoRep: A flexible tool for spatial representation of line drawings. " Proceedings of the 18th National Conference on Artificial Intelligence. Austin, Texas: AAAI Press. 2000
- Ferguson, RW, Bokor, JL, Mappus, RL, & Feldman, A ..: " Maintaining spatial relations in an incremental diagrammatic reasoner." Conference on Spatial Information Theory, Ittingen, Switzerland, September 2003