Explain the Advantage and disadvantage of vectors methods.
Answers
Advantages :
Data can be represented at its original resolution and form without generalization.
Graphic output is usually more aesthetically pleasing (traditional cartographic representation);
Since most data, e.g. hard copy maps, is in vector form no data conversion is required.
Accurate geographic location of data is maintained.
Allows for efficient encoding of topology, and as a result more efficient operations that require topological information, e.g. proximity, network analysis.
Disadvantages:
The location of each vertex needs to be stored explicitly.
For effective analysis, vector data must be converted into a topological structure. This is often processing intensive and usually requires extensive data cleaning. As well, topology is static, and any updating or editing of the vector data requires re-building of the topology.
Algorithms for manipulative and analysis functions are complex and may be processing intensive. Often, this inherently limits the functionality for large data sets, e.g. a large number of features.
Continuous data, such as elevation data, is not effectively represented in vector form. Usually substantial data generalization or interpolation is required for these data layers.
Spatial analysis and filtering within polygons is impossible