GEO 141 Test#1
← What is GIS ?
• Geographical Information Systems
← Why use GIS?
To create and analyze maps, photographs, satellite images
← Why analyze them?
• To see information (data) on a visual form to identify relationships,
← GIS can be used for:
• Choosing the most effective way to build/take down buildings
• Protecting forestry
• Buffer: customer spotting (taking postal codes)
← Distance Decay: The further away the data from a location the less
amount of data. It is a function that represents the way that some entity or its
influence decays with a distance from its geographical location.
← Ecological Fallacy: a problem associated with the “modifiable areal unit
problem” that occurs when it is inferred that data for areas under study can
be applied to individuals in these areas. The assumption that an individual
from a specific group or area will exhibit a trait that has predominant to the
group as a whole.
← Raster Data Model: system of tessellating rectangular cells in which
individual cells are used as building blocks to create images of point, ling,
area, network, and surface entities. A representation of the world as a surface
divided into a regular grid of cells. Raster models are useful for storing data
that varies continuously, as in an aerial photograph, a satellite image, a
surface of chemical concentrations, or an elevation surface.
← Choropleth Map: a thematic map that displays a quantitative attribute
using ordinary classes. Areas are shaded according to their value and a range
of shading classes. A thematic map in which areas are distinctly colored or
shaded to represent classed values of a particular phenomenon.
← ← Vector Data Model: a spatial data model using two-dimensional
cartesion (x,y) co-ordinates to store the shape of spatial entities. A
representation of the world using points, lines, and polygons. Vector models
are useful for storing data that has discrete boundaries, such as country
borders, land parcels, and streets.
← Intervening Opportunities: The existence of a closer, less expensive
opportunity for obtaining a good or service, or for a migration destination.
Such opportunities lessen that attractiveness of more distance places.
← Census Tract: A small, statistical subdivision of a county that usually
includes approximately 4,000 inhabitants but may include from 2,500 to
8,000 inhabitants. A census tract is designed to encompass a population with
relatively uniform economic status, living conditi