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Geospatial Ontology: An Introduction


What we call “geographical data” includes different kinds of data. We observe the natural world when we get data about topography, landscapes, the oceans and the atmosphere. Sometimes we represent data from nature as a continuous variation, as when we build digital terrain models. In other situations, we give names to natural features, as when we say “Mont Blanc”. We also create geographical reality, as when we draw boundaries of countries and of land parcels. We also measure facts of the social world, when we take a census and locate crimes. We also build continuous distributions out of social reality, e.g., when we create maps of disease incidence in a country. We also observe and detect change in the geographical world, as when we map new deforested areas.

Ontologies of the geographic world are important to allow the sharing of geographic data among different communities of users. A geo-ontology provides a description of geographical entities, which can be conceptualised in two different views of the world. The field view considers spatial data to be a set of continuous distributions. The object view conceives the world as occupied by discrete, identifiable entities. Objects and fields are not merely located in space, they are tied intrinsically to space. However, to properly represent changes, it is also necessary to describe concepts that convey the dynamics of spatial phenomena. The notions of events and processes are useful to explicitly include the temporal dimension. The lectures present a general overview of the main trends in Geospatial Ontology, discussing the concepts of objects, fields and events for representation of geographical phenomena. The course also highlights the specific area of land use and land cover ontology, an area of considerable importance for geospatial ontology research.

The beauty and the challenge of Geoinformatics is that there are a relatively small set of data structures that are able to represent different types of geographical data. This representational power has enabled software engineers to develop the technology of geographical information systems. The challenge is to understand both the data structures and the semantics of the information they represent. This course is then focused on discussing the semantics of geographical data, as well as the links between such semantics and the associated computer representation. When they complete the course, we expect that students should be able to understand the different types of geographical data and how they are represented in computers.


The motivation for this course came from the need to establish a set of foundational concepts to the field of Geoinformatics. To do this, we will examine reference papers published in the literature that are relevant to Geoinformatics researchers and practicioners.


The course is organised on the following main topics:

  1. What is Geoinformatics? General definitions. Linking computer representations to geographical data. General examples.
  2. Geometries for representing the social world: points, lines and polygons. Topological relations.
  3. Representing the world: putting the Earth into a computer. Location as a key property of the world.
  4. Representing the social world: generation geographical reality with our laws and social arrangements. The role of boundaries. Creating (fiat) objects. The need for maintaining identity of objects of the social world.
  5. Describing the natural world, part I: assigning names, identities and (bona fide) boundaries to places and features of the world and to living beings. The inherent ambiguity of “places”.
  6. Describing the natural world, part 2: measuring properties of the world as continuous distributions. Fields as a general data type for measuring the world.
  7. Describing change: the concepts of trajectories, moving objects, and events.

Course Offerings

geo-ontology.txt · Last modified: 2016/08/10 19:32 by gilberto