Direction as a spatial object: A summary of results

Shashi Shekhar, Xuan Liu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations

Abstract

Direction is an important spatial relationship that is used in many fields such as geographic information systems(GIS) and image interpretation. It is also frequently used as a selection condition in spatial queries. Previous work has modeled direction as a relationship predicate between spatial objects. Conversely, in this paper, we model direction as a new kind of spatial object using the concepts of vectors, points and angles. The basic approach is to model direction as a unit vector. Given an ordered pair (p1,p2) of spatial points, one can define a direction, which can take the values of North, Northwest, 3 o'clock, etc. to represent the corresponding qualitative directional predicates on (p1,p2) in previous work. Direction objects can also have quantitative operations such as direction-composition and direction-reverse. This novel view of direction has several obvious advantages: First, it allows us to define the orientation of spatial objects; Second, a richer set of predicates and operators on direction and orientation can be defined; Third, new spatial data types such as oriented spatial objects and unbounded spatial objects can be defined. Finally, the object view of direction makes it easy to do direction reasoning, which is useful in spatial query processing and optimization.

Original languageEnglish (US)
Title of host publicationProceedings of the 6th ACM International Symposium on Advances in Geographic Information Systems, GIS 1998
PublisherAssociation for Computing Machinery
Pages69-75
Number of pages7
ISBN (Electronic)1581131151
DOIs
StatePublished - Nov 1 1998
Event6th ACM International Symposium on Advances in Geographic Information Systems, GIS 1998 - Washington, United States
Duration: Nov 2 1998Nov 7 1998

Publication series

NameGIS: Proceedings of the ACM International Symposium on Advances in Geographic Information Systems
VolumePart F129244

Other

Other6th ACM International Symposium on Advances in Geographic Information Systems, GIS 1998
Country/TerritoryUnited States
CityWashington
Period11/2/9811/7/98

Bibliographical note

Funding Information:
1This -work is sponsored in part by the Army High Performance Computing Research Center under the auspices of the Department of the .kw, AmY Research Laboratory ~oper’ati~re asreemmt n~ber DAAI%04-9S-2-0003/contract number DA.AH04-95-GOO08, the content of whkb does not necessarily reflect the position or the policy of the government, and no official endorsement should be inferred. This work was afso supported in part by NSF grant #9631539.

Funding Information:
This -work is sponsored in part by the Army High Performance Computing Research Center under the auspices of the Department of the Army, Army Research Laboratory co-operative agreement number DAAH0495-2-0003/contract number DAAH0495-GOC)08, the content of which does not necessarily reflect the position or the policy of the government, and no official endorsement should be inkred. This -work was also supported in part by NSF grant #9631539 Thanks to Dr. Sanjay Chawla for technical commentary and to Christiame McCarthy for helping to improve the readabd-ity of the paper.

Publisher Copyright:
© 1998 ACM.

Keywords

  • Direction
  • Orientation
  • Oriented spatial object
  • Unbounded object

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