One Datasource Many Views

Thursday, September 15, 2005

A GIS Is Like A Database

  • GIS does not store maps

  • GIS stores information from which maps can be made

  • maps are like views in a database \x96 one set of tables, many views

  • examples of "views"

  • scale - change extent of "ground" shown on the map (larger the number => smaller the scale => more the area shown => less the detail)

  • projection - map projections represent spherical shapes on flat surface (Mercator, Albers, Lambert)

  • isopleth - represent continuous area data that varies smoothly over space (contours, isohyet, isotherm, isobar, isohume)

    choropleth - each spatial unit is filled with a uniform color or pattern (tax maps, density maps, land use)

  • GIS allows [Spatial Analyses] of mappable data

GIS manages info that can be [Spatial or Non-Spatial]