[AM3-5] Proximity and distance decay

Proximity computations are specific neighbourhood functions. They evaluate the characteristics of an area surrounding a feature’s location. A neighbourhood function “scans” the neighbourhood of the given feature(s), and performs a computation on it (them). Examples of proximity computations are: (1) Buffer zone generation (or buffering) is one of the best-known neighbourhood functions. It determines a spatial envelope (buffer) around a given feature or features. The buffer created may have a fixed width or a variable width that depends on characteristics of the area. (2) Thiessen Polygon generation. Distance decay functions describe the effect of the reduced influence when the distance between two locations increases.

External resources

• ITC (2013) The Core of GIScience: A Process-based Approach. ITC educational textbook series. 524 pages. ISSN 1567-5777. ISBN 978-90-3653-719-3.

Learning outcomes

• 138 - Describe real world applications where distance decay is an appropriate representation of the strength of spatial relationships (e.g., shopping behavior, property values)
  Describe real world applications where distance decay is an appropriate representation of the strength of spatial relationships (e.g., shopping behavior, property values)
• 139 - Describe real world applications where distance decay would not be an appropriate representation of the strength of spatial relationships (e.g., distance education, commuting, telecommunications)
  Describe real world applications where distance decay would not be an appropriate representation of the strength of spatial relationships (e.g., distance education, commuting, telecommunications)
• 140 - Explain the rationale for using different forms of distance decay functions
  Explain the rationale for using different forms of distance decay functions
• 141 - Explain how a semi-variogram describes the distance decay in dependence between data values
  Explain how a semi-variogram describes the distance decay in dependence between data values
• 142 - Outline the geometry implicit in classical gravity models of distance decay
  Outline the geometry implicit in classical gravity models of distance decay
• 143 - Plot typical forms for distance decay functions
  Plot typical forms for distance decay functions
• 144 - Write typical forms for distance decay functions
  Write typical forms for distance decay functions
• 145 - Write a program to create a matrix of pair-wise distances among a set of points
  Write a program to create a matrix of pair-wise distances among a set of points

Self assessment

Outgoing relations

• [AM3-5] Proximity and distance decay subclassof [AM3] Geometric measures
• [AM3-5] Proximity and distance decay subclassof [AM4-4] Neighborhood analysis

Contributors

• Rob Lemmens
  University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC)
  https://research.utwente.nl/en/persons/rob-lemmens