5) Geographic Information System

5) Geographic Information System

1. What is it?

   • A system involving people, social structures and technology

2. Purpose

   • Process and provide information
     • GIS links spatial data and database information and enables the visualization of patterns etc

3. Characteristics

   • Attribute data
     • Name, phone number, address etc.
   • Distributed data
   • Institutional framework, support and maintenance
   • Analysis Tools

4. Components

   • Software
   • Data
   • Methods
   • People
   • Hardware

5. Functions

   • Data aquisition and input
     • Data storage
       • Data retrival
         • Data manipulation and analysis
           • Data output
             • Maps, reports, charts
           • Simple searches, network analysis, buffering, corridor analysis, boolean analysis
         • Data representation
           • map making, charts, tables, etc.
         • Method of retrieval, access to data
       • Storage medium, storage format, distribution of dtata
     • surveys, acquired data, graphic data

6. Spatial data models

   • Vector model
     • Point
     • Line
     • Polygon
     • Each polygon/line/point is assigned an attribute
     • Advantages
       • Greater location accuracy
       • can store detailed attribute information
       • Less storage volume
     • Disadvantages
       • More complex computtion
       • Complex data structure
       • Not all phenomena can be modeled by hard boundaries
   • Raster model
     • each cell is assigned an attribute
     • Cells → Raster
     • Advantages
       • Easy to perform calculations
       • Simple data structure
       • Easy to apply to mathematical modeling applications
     • Disadvantages
       • Large storage volume
       • Data has blocky apperance
       • Inaccurate boundaries

7. Topology

   • Relative spatial arrangement of geometric shapes in space
     • Determination of adjacency, containment, etc.

8. Metadata

   • Data about data
     • Age, Origin, Medium
   • Allows to make informed decisions as to whether the data is suitabe