| 7.2.8 Data
processing and analysis
Proximity analysis (buffer,
distance calculation), spatial joins (overlay), network analysis, generalisation
or smoothing, region boundary dissolving and many other fundamental GIS
functions fall within this very broad class. Such functions will differ
significantly depending on the data structure (raster or vector) used by
the system. For example, network analysis is almost impossible with a grid
structure; while neighbourhood analyses, such as the production of a simple
slope map, are difficult with vector data. In general, grid-based GIS are
feasible or optimal where the objects to manipulate are essentially points
or regions which require an intensive use of interpolation, filtering and
overlay functions. Vector GIS are more efficient when linear features must
be handled and large databases should be linked to the spatial features.
Optimal GIS incorporate both vector and grid functionality. Sometimes,
it is recommended a strategy based on the transformation of the spatial
data from one structure to another. In certain circumstances, the approach,
which may appear cumbersome and time consuming, is the only feasible way
to face problems otherwise unmanageable.
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in order to see a larger
version of this photo
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Here we have
two examples of using a GIS for analyzing data, aiming to the production
of thematic maps & finally, for decision making (both refer to Peristeri
municipality - Athens). The first shows the areas that are well served
by public transportation (buffers) & the second, the urban areas that
establishment of amusement uses must be forbidden (circles that define
200 m range from schools).
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