An Area Merge Operation for Smooth Zooming

  • Radan Šuba
  • Martijn Meijers
  • Lina Huang
  • Peter van Oosterom
Part of the Lecture Notes in Geoinformation and Cartography book series (LNGC)


When zooming a digital map it is often necessary that two or more area features must be merged. If this is done abruptly, it leads to big changes in geometry, perceived by the user as a “jump” on the screen. To obtain a gradual merge of two input objects to one output object this chapter presents three algorithms to construct a corresponding 3D geometry that may be used for the user’s smooth zooming operations. This is based on the assumption that every feature in the map is represented in 3D, where the 2D coordinates are the original representation, and 1D represents the scale as a Z value. Smooth zooming in or out is thus equivalent to the vertical movement of a horizontal slice plane (downwards or upwards).


Delaunay Triangulation Opposite Boundary Slice Plane Vertical Face Tilted Plane 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This research is supported by the Dutch Technology Foundation STW (project number 11185), which is part of the Netherlands Organisation for Scientific Research (NWO), and which is partly funded by the Ministry of Economic Affairs. Furthermore, we would like to thank the anonymous AGILE reviewers and Rod Thompson for their constructive comments, suggestions and questions. Extra thanks to Rod for correcting our English.


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Radan Šuba
    • 1
  • Martijn Meijers
    • 1
  • Lina Huang
    • 1
    • 2
  • Peter van Oosterom
    • 1
  1. 1.Section GIS Technology, OTB—Research for the Built EnvironmentDelft University of TechnologyDelftThe Netherlands
  2. 2.School of Resource and Environmental ScienceWuhan UniversityWuhanChina

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