Presentation on theme: "Maps: Two-dimensional, scaled representations of Earth surface - show spatial data (data with locational component) Cartography (map-making) involves 5."— Presentation transcript:
Maps: Two-dimensional, scaled representations of Earth surface - show spatial data (data with locational component) Cartography (map-making) involves 5 design decisions – based on purpose of map Projection Simplification Scale Aggregation Type of Map (thematic* or reference)
THEMATIC MAPS – depict characteristics of places Categorical type - Depict areas that are different in kind - Use several distinct colors to show different categories desertforesttundra Examples: climates, religions Choropleth type - Depict areas that are different in amount - Use shades of similar colors to show different values high valuemediumlow value Examples: population density, literacy rates
Example of “choropleth map” Human Development Index (HDI) Rankings Includes GNI/PPP, Literacy, and Life Expectancy Which regions have high HDI? Which regions have low HDI? Which places are exceptions?
Isoline type (Average Daily Solar Radiation) Lines connect points of equal value Dot Density type (Wisconsin Acreage in Potatoes) Each dot represents a frequency of mapped variable
Proportional Symbol Map (Graduated Circle type) Size of symbol varies in relation to frequency or intensity of the mapped variable Proportional Symbol Map (Flow Vector type)
Sample Map Projections Mercator Systematic methods of transferring a spherical surface to a flat map Distortion must occur in either size, shape, distance, or direction – all projections are compromises RobinsonPolar
Equal-Area projections best where purpose is to compare distributions of a variable between places (They distort shapes to make sizes correct.) What impressions do you get from this map?
smaller scale Sample Area CoveredFraction ScaleVerbal Scale World1:78,000,0001 in = 1,250 mi No. America1:36,000,0001 in = 570 mi Central U.S.1: 4,000,0001 in = 64 mi AAA Colo map1: 1,267,2001 in = 20 mi larger scale Smaller-scale shows more land area in less detail. Used to show global patterns. Larger-scale shows less land area in more detail. Used on local maps. Map Scale The ratio of map distance to earth distance, measured in the same units
The scale at which one analyzes an issue is critical DIA – Only major U.S. airport built since 1980 At the national scale, why did the location of this airport make sense? At the local scale, why was it necessary to locate the airport where it is?
Percent of 1990 pop age 25+ with bachelor's degree Data aggregated by State Map Aggregation The level of detail for dividing a thematic map into geographic units Ranges from coarse divisions (e.g., by countries) to fine divisions (e.g., by zip codes)
Percent of pop age 25+ with bachelor's degree (1990) Note what information is lost at higher levels of aggregation Aggregated by State (northeast close-up) Aggregated by County (WV, MA)
Source: M. Gastner, C. Shalizi, and M. Newman, University of Michigan http://www-personal.umich.edu/~mejn/election/ State results, by land area County results, by land area State results, by population County results, by population 2004 Presidential Election Red = Bush; Blue = Kerry
Source: M. Gastner, C. Shalizi, and M. Newman, University of Michigan http://www-personal.umich.edu/~mejn/election/ 2004 Presidential Election Red = Solidly Bush (70% +) Purples = divided … redder = Bush majority; bluer = Kerry majority Blue = Solidly Kerry (70%+) By land areaBy population
Spatial Thinking (Phil Gersmehl, Research in Geographic Education, 2006)
Pattern Analysis: Density vs. Dispersion Which square mile has the higher density, (a) or (b)?
Various Pattern Arrangements What phenomena could explain the patterns shown in A, B, and C?
Connections What kinds of things are symbolized by lines on this map?
Combination of climate, agriculture, and industry explains population density patterns Where are some patterns that illustrate this?
Denver metro area How does this map illustrate the aura or zone of influence for Denver? How are hierarchies symbolized on this map? For which kinds of services does Denver’s aura extend beyond this map?
Where could you define a region of “Elvis-lovers”? Where are the exceptions? Where are the outliers?
Compare the Pacific coasts of North and South America Which places have analogous climates?
Spot any spatial correlations? Middle & South America Agricultural Regions (left) and Population Density (below)
Christian An example of the importance of spatial thinking
TURKIC (Altaic Language Family) IRANIAN (Indo-European Language Family) SEMITIC (Afro-Asiatic Language Family) Diversity, exceptions, and edges can make for interesting case studies or examples
Iraq’s population is 29 million: sixty percent are Shi’a Arab, mostly in the south. Sunni Arabs are concentrated in the center (western Iraq is sparsely populated). Over 4 million Iraqis in northern Iraq are Kurdish. Baghdad is a transition zone. Saudi Arabia Kuwait Iran Jordan Syria Turkey Iraq Ethnic Groups Knowledge of cultural regions, boundaries, and transitions is necessary for understanding conflicts