Geography Ch. 2

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 Earth’s 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
• 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

• 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.

• Epidemiologists need accurately mapped information to study both the diffusion of diseases, such as malaria, SARS, AIDS, and dengue fever, and entomological risk factors.

• 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.

• 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 0° (the equator) to 90° (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 0° to 180°

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 Earth’s reality

are used when a map is intended to show the actual areal extent of a phenomenon on Earth’s surface

conformal projections

true shape projections

azimuthal projections

Directions are true from one central point to all others
• 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 earth’s surface

area cartogram

• Areas of units are drawn proportional to the data they
represent.
• Sizes and shapes of areas may be altered.
• Distances and directions may be distorted.
• Contiguity may not be preserved.

line symbols

Represent features that have length but insignificant width

flow-line map

• Flow lines have varying proportional widths representing volumes of flow.
• 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 18–30 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