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Lecture

GIS Information Systems properties and information on GIS information systems


Department
Geography
Course Code
GG102
Professor
Sean Doherty

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January 17th, 2011
GIS – geographic information system
- modern day maps
- powerful analysis techniques
What is it?
-automated system for the capture, storage, retrieval analysis and display of spatial data
ex. Google earth
Made up of layers of data
Vector – customers
streets
parcels
Raster- elevation
land usage
Raster data – grid (pixels)
Vector data – graph
“Primitive” Data Types
-points
-lines
-polygons
-surfaces
Points
- aka “Nodes”
-can represent anything
- assigned either X or Y co-ordinate
-attributes can be assigned (quantitative, qualitative) ex. Colour
Lines
-have length, no width
-bounded by points (always ended by a point)
-Attributes length, flows, roads
Polygons
-“areas”
-have lengths and widths
-bounded by lines
-Attributes states, zones, bodies of water, footprint of building
-convey spatial distributions
Surfaces
-polygons with a 3rd dimension
-length, width and height (contours)
-used to represent elevation ,volume, buildings
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