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distance
direction
topographic maps and terrain representation
They usually portray the surface features of relatively small areas, often with great accuracy. They not only show landforms, streams, and other natural features but also may display things that people have added to the natural landscape. These include transportation routes, buildings, and such land uses as orchards, vineyards, and cemeteries. Many types of boundaries, from state borders to field or airport limits, are also depicted on topographic maps.
thematic maps and data representation
The study of the spatial patterns and interrelationships of things, whether people, crops, or traffic flows
qualitative map is to show the distribution of a particular class of information
quantitative thematic maps show the spatial characteristics of numerical data
point symbols
Features that occur at a particular point in space
ex: houses of worship, schools, cemeteries, and historical sites
Symbols used to represent them include dots, crosses, triangles, and other shapes
land survey systems
area symbols
Features found within defined areas of Earthās surface
two general categories: those showing differences in kind and those showing differences in quantity
Contains numerous examples of the first category, such as patterns of religions, languages, political entities, vegetation, or types of rock
Different colors or patterns are used for different areas
line symbols
features that have length but insignificant width
represent rivers, political boundaries, roads, and railroads, for example, are not quantitative
map misuse
Lack of a scale. A scale may be absent and the sizes of some areas diminished while others are enlarged.
A simple design that omits data or features that would make the map more accurate.
Colors that have a strong psychological impact.
Bold, oversized, and/or misleading symbols.
Action symbols, such as arrows to indicate military invasions or repulsions and pincers to show areas threatened by encirclement
remote sensing
obtaining geographic data without direct contact with the ground
the global positioning system
A GPS receiver records the positions of a number of the satellites simultaneously, then determines its latitude, longitude, and altitude and the time.
virtual and interactive systems
web applications that combine data from more than one source into an integrated experience
the geographic grid
a set of imaginary lines that intersect at right angles to form a system of reference for locating points on the surface of Earth
ā¢ North and South Poles, equator, prime meridian
area
the geographic database
a digital record of geographic information from maps, field surveys, aerial photographs, or satellite imagery
shape
application of GIS
ā¢ Biologists and ecologists use GIS to study numerous environmental problems, including air and water pollution, landscape conservation, wildlife management, and the protection of endangered species.
ā¢ Epidemiologists need accurately mapped information to study both the diffusion of diseases, such as malaria, SARS, AIDS, and dengue fever, and entomological risk factors.
ā¢ GIS software has made it possible for political scientists to evaluate existing legislative districts, using criteria such as compactness and contiguity, and to suggest ways the boundaries of the districts might be redrawn.
ā¢ Sociologists have used GIS to identify clusters of segregation and to examine the changing structures of segregation over time.
systems, maps, and models
computerized map-making systems
GIS- geographic information system
a computer-based set of procedures for assembling, storing, manipulating, analyzing, and displaying geographically referenced information
1. a data input component that converts paper maps, data tables, and location data into digital form
2. a data management component to store and retrieve data
3. data manipulation functions to use disparate sources simultaneously
4. analysis functions to extract useful information from the data
5. a data output component to visualize maps and tables on the computer monitor or as hard copy (such as paper)
the globe properties
1. All meridians are of equal length; each is one-half the length of the equator.
2. All meridians meet at the North and South Poles and are true north-south lines.
3. All parallels of latitude are parallel to the equator and to one another.
4. Parallels decrease in length with distance from the equator.
5. Meridians and parallels intersect at right angles.
6. The scale on the surface of the globe is everywhere the same in all directions.
properties of maps
area, space, distance, direction
ways scale is represented
verbally, graphically, or numerically as a representative fraction
large and small scale maps
small scale maps show less detail, non-accurate measurement
choropleth maps
The data are grouped into a limited number of classes, each represented by a distinctive color, shade, or pattern
cartography
art, science, and technology of making maps
latitude
the angular distance north or south of the equator, measured in degrees ranging from 0Ā° (the equator) to 90Ā° (the North and South Poles)
prime meridian
an imaginary line passing through the Royal Observatory at Greenwich, England. This prime meridian was selected as the zero-degree longitude
longitude
the angular distance east or west of the prime (zero) meridian measured in degrees ranging from 0Ā° to 180Ā°
international date line
where each new day begins, generally follows the 180th meridian
map projection
the way the curved surface is represented on a flat map
equal-area projection
the areas of regions in correct or constant proportion to Earthās reality
are used when a map is intended to show the actual areal extent of a phenomenon on Earthās surface
conformal projections
true shape projections
azimuthal projections
Directions are true from one central point to all others
ā¢ Directions from other points are not accurate.
May also be equivalent, conformal or equidistant
robinson projection
Compromise between equal-area and conformal
Does not show true distances or directions
topographic map
depict the shape and elevation of the terrain
contour line
the principal symbol used to show elevation on topographic maps
contour interval
the vertical spacing between contour lines
point symbols
Various symbols (for example, dot, triangle, star) represent features that occur at particular points in space; for example, village, church, school
dot density map
each dot represents a given quality
graduated symbol map
size of symbol varies according to quantities represented
area symbols
Different colors or patterns represent features found within defined areas (for example, counties, states, countries) of the earthās surface
area cartogram
ā¢ Areas of units are drawn proportional to the data they
represent.
ā¢ Sizes and shapes of areas may be altered.
ā¢ Distances and directions may be distorted.
ā¢ Contiguity may not be preserved.
line symbols
Represent features that have length but insignificant width
flow-line map
ā¢ Flow lines have varying proportional widths representing volumes of flow.
ā¢ May also depict route taken and direction of movement
false-color images
color-infrared technology
thermal scanners
record the longwave radiation emitted by water bodies, clouds, and vegetation, as well as by buildings and other structures and are used to produce images of thermal radiation
radar system scanners
useful for monitoring the locations of airplanes, ships, and storm systems and for mapping parts of the world that are perpetually hazy or cloud-covered
lidar system scanners
a remote-sensing technology that utilizes an airborne laser that sends hundreds of thousands of pulses of light every minute
three-dimensional models of buildings, trees, and the ground surface
landsat satellites
remote-sensing spacecraft
utilized for immediately monitoring, mapping, and responding to natural and human-caused disasters, such as storms, floods, droughts, earthquakes, volcanoes, wildfires, and oil spills
GNSS- global navigation satellite systems
a system of 18ā30 orbiting satellites, Earth-bound tracking stations that control the satellites, and portable receivers that determine exact geographic locations based on the time delay in signals received from three or more satellites
global positioning systems
A GPS receiver records the positions of a number of the satellites simultaneously, then determines its latitude, longitude, and altitude and the time
geocaching
geographic database
a digital record of geographic information from maps, field surveys, aerial photographs, or satellite imagery
A Representative Fraction
Scale
the ratio between the measurement of something on the map and the corresponding measurement on Earth
A Thematic (special-purpose) Map
The study of the spatial patterns and interrelationships of things, whether people, crops, or traffic flows, is the essence of geography
Spot heights
numbers indicate elevation of selected points
Bench marks
a particular type of spot height, is used as a
reference in calculating elevations of nearby locations
Mashups
digital maps merged with data from other sources, interactive maps