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Exam 1
Introduction to Geographic Information Systems
78
Geography
Undergraduate 4
03/01/2011

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Term
Define both geographic information systems as a toolbox and geographic information science
Definition
Toolbox: GIS TRANSFORMS data
Geographic Information Science: built to provide answers to questions
Term
Know what makes GIS unique from related technologies (know what these technologies are)
Definition
Term
Understand the historical development of GIS
Definition
Term
What are projections and their properties?
Definition
Term
What accuracies and distortions have to do with projections?
Definition
Term
What are the basic ways of classifying projections? (e.g., by developable surface)
Definition
Term
Suggest an appropriate projection for mid latitude continents.
Definition
Term
Suggest an appropriate projection for global representations.
Definition
Term
What form of projection is good for representing population density?
Definition
Term
What is the UTM coordinate system and why is it used?
Definition
Term
What is the state plane coordinate system and why is it used?
Definition

Grid based method of specifying locations on the surface of the earth, practical application of Cartesian.

Used to identify locations independent of altitude.

Term
Define data models.
Definition
Term
Define raster.
Definition
raster graphics image or bitmap is a data structure representing a generally rectangular grid of pixels, or points ofcolor
Term
What implementation issues exist with the raster data model? (resolution, mixed pixel problem)
Definition
Term
What are the basic ways to locate or produce data for use in GIS?
Definition
Term
Identify 3 online GIS data sources.
Definition
„ Meetings(and(Proceedings
± www.giscience.org
„ Electronic(newsletters
± www.geoPlace.com
„ Professional(organizations
± www.ucgis.org
Term
Describe the process of digitization.
Definition
Term
What are the common digitizing errors?
Definition
Term
Standard lines/parallels=
Definition
points of tangency or intersection between developable surfaces and 3D globe
Term
3 aspects of a projection:
Definition
Normal
Transverse
Oblique
Term
Conformal projections preserve:
Definition
Shapes
Term
Equivalent projections preserve:
Definition
Areas
Term
T or F: Maps can be both conformal and equivalent.
Definition
False
Term
T of F: To compare maps or data in GIS you need to have data in the same projection or at least the same type of projection (conformal or equivalent).
Definition
True
Term
What are the 3 light source map projections?
Definition
Gnomonic
Antipodal
Orthographic
Term
Gnomonic
Definition
light at center of globe
Term
Antipodal/stereographic
Definition
pole to pole light source
Term
Orthographic
Definition
light source from an infinite distance away
Term
What is a great circle?
Definition
Term
What does scale size refer to?
Definition
The ratio between the size of the thing in the map and the size of the thing in the real world.
Term
Small scale maps see a larger portion
Definition
Term
Large scale maps see a smaller portion
Definition
Term
What does a GIS consist of (at the least)?
Definition
database
map information
computer-based link between the two
Term
Define GIS as a toolbox.
Definition
a powerful set of tools for storing and retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes.

automated systems for the capture, storage, retrieval, analysis, and display of spatial data.

gis are simultaneously the telescope, the microscope, the computer, and the Xerox machine of regional analysis and synthesis of spatial data.
Term
Define GIS as an information system.
Definition
An information system that is designed to work with data referenced by spatial or geographic coordinates. In other words, a GIS is both a database system with specific capabilities for spatially-referenced data, as well as a set of operations for working with the data.
Term
What is a feature?
Definition
A cartographic term that refers to something placed on a map.
Term
Define GIS as an approach to Science.
Definition
focus on generic issues that surround the use of GIS technology, impede its successful implementation, or emerge from an understanding of its potential capabilities.
Term
Define GIS as a multi-billion dollar business.
Definition
Billions of $ spent every year on GIS software and data, and on the hardware
Term
Define GIS as a social structure.
Definition
organized activity by which people measure and represent geographic phenomena, and then transform these representations into other forms while interacting with social structures
Term
What are some ways that geographic information is involved in our daily lives?
Definition
land ownership, property transfer, navigation, weather, transportation, utilities
Term
Why has there been such a growth is GIS?
Definition
basic needs of society
push to the desktop - technology
software improvements
educated user base
inexpensive data
Term
Why has there been such a growth is GIS?
Definition
basic needs of society
push to the desktop - technology
software improvements
educated user base
inexpensive data
Term
What did the Land Ordinance of 1785 do?
Definition
Called for the systematic survey and subdivision of lands that were "being acquired" by the U.S. - US Public Land Survey
Term
What is Dr. John Snow known for?
Definition
Formulated hypothesis that cholera is spread through contaminated water supplies after examining a map of London.
Term
What are gores?
Definition
Sections of maps pasted to a rigid sphere.
Term
What is a map projection?
Definition
Transformation of a spherical or ellipsoidal earth onto a flat map.
Term
What is a developable surface?
Definition
A surface that is flat or can be made flat by cutting.
Term
What are the 3 main developable surfaces?
Definition
Plane- Azimuthal
Cylinder- Cylindrical
Cone- Conic
Term
Why do secant projections minimize the maximum errors?
Definition
The longest distance from the intersection lines to the sphere is reduced.
Term
What are the 3 aspects to projections depending on where the tangency/secancy occurs?
Definition
Normal
Transverse - 90 degrees rotation is usual
Oblique - what's left
Term
What is a coordinate system?
Definition
A standardized method for assigning codes to locations so that locations can be found using codes alone.
Term
What coordinate systems are used in the U.S. (4)?
Definition
geographic coordinates (lat/long)
universal transverse mercator
military grid
state plane
Term
Give some characteristics of UTM (Universal Transverse Mercator).
Definition
 Based on 60 different transverse
aspect Mercator projections to minimize
error in each zone– 1 part in 2500.
 Extends from 80°S to 84°N.
 Polar areas covered by UPS (not the
people with the brown trucks, but
Universal Polar Stereographic)
Term
Give some characteristics of State Plane= Local Projections.
Definition
 Zones that are mostly E-W (e.g. Iowa) are
based on local Lambert Conic projection
 Zones that are N-S (e.g. Illinois) are based on
a local transverse aspect Mercator that is NOT
the same as the UTM at that location
 Originally restricted to distance of 158 miles
orthogonal to secant to limit distortion
 Error 1 part in 10,
Term
What type of projection would you use if density is important?
Definition
Equal area projection
Term
A logical data model is?
Definition
How data are organized for use by GIS.
Term
Edmund Halley
Definition
Clerk at Royal Society of London
Knew many geodetic scientists
editor of philosophical transactions
Term
What is cartography?
Definition
Process of transformation and abstraction from complex reality to simplified map cognition
Term
Graticule
Definition
set of intersecting lines of latitude and longitude that provides indicators of direction and also about the type of projection involved
Term
What does a location map do?
Definition
Provides info about transportation and sites of interest
Term
What are cadastral maps?
Definition
Show land ownership parcels
Term
What is a contour (or isoline)?
Definition
Connects places with equal magnitude.
Term
What does a topographic map show?
Definition
Elevations with contour lines
Term
Dot maps are a type of thematic map.
Definition
Term
What does a chloropleth map show?
Definition
Values of data within areas by using shading.
Term
What do cartograms show?
Definition
The magnitudes of variables by changing areas - intentional distortion is used.
Term
Graduated symbol map?
Definition
Proportional circles used.
Term
Flow map
Definition
Legend is vague with no units
Term
What is geocoding?
Definition
Conversion of spatial info into digital form
Involves capturing the map and attributes
May involve address matching
Term
What are some geocoding methods for maps?
Definition
Digitizing
Scanning
Field data collection
Term
What is digitizing?
Definition
captures map data by tracing lines from a map by hand
uses a cursor and tablet
Term
What are some errors associated with digitizing?
Definition
Slivers
duplicate lines
duplicate nodes
unended lines
gaps
Term
What are some errors associated with scanning?
Definition
grid of pixels
features can "drop out"
Term
Attribute data
Definition
logically can be thought of as in a flat file
table with rows and columns
attributes by records
entries called values
Term
What are the elements of database?
Definition
Type of value
Range
Missing data
Duplicate data
Key
Term
What is the role of error?
Definition
Map and attribute data errors are the data producer's responsibility, but the GIS user must understand error
Accuracy and precision of map and attribute data in a GIS affect all other operations
Term
Spatial data are unique because:
Definition
they are linked to maps
Term
What does a photomap consist of?
Definition
Remote sensing image and cartographic images.
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