HOME ENV510 Landscape Ecology and GIS

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Vector

In the vector (or topological) data structure information is stored as points, lines and polygons. A polygon is an area bounded by a closed loop of straight line segments (Aranoff, 1989).

This sort of representation is similar to how objects would be shown on a map. The position of each object is defined by its placement in a map space that is organised by a coordinate reference system.

Vector contours

Advantages and disadvantages of vector data structures

Advantages

• Data storage is relatively more compact than the raster model
  
  
• Editing data sets is straightforward
  
  
• They produces high quality output ie vector structures are better suited to the production of graphics that resemble hand drawn maps
  
  
• They allow complex analysis to be performed flexibly
  
  
• They allow spatial links or topology between features to be included in the data set
  

Disadvantages

• It is a much more complex data structure than the simpler raster model
  
  
• Overlay operations are more difficult
  
  
• The representation of high spatial variability is inefficient
  
  
• It is computationally more intensive to perform tasks using a vector structure than using a raster model
  
  
• Vector structures cannot effectively manipulate and enhance digital images

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