CHAPTER 3 VOCABULARY TERMS DEFINED
equator – halfway point between the poles that cuts the Earth in half
minutes – 1/60 of a degree
seconds – 1/60 of a minute
prime meridian – the meridian at 0o that passes through Greenwich, England
great circle – any circle that divides the globe into halves, or marks the circumference of the globe
geomagnetic poles – areas on Earth’s surface just above where the poles of the imaginary magnet would be
magnetic declination – the angle between the direction of the geographic pole and the direction in which the
compass needle points
global positioning system – a satellite navigation system that is based on a global network of 24 satellites that
transmit radio signals to Earth’s surface
cartography – science of making maps
cartographers – scientists that make maps
cylindrical projection – a lighted, transparent sphere that is wrapped with a cylinder of paper
azimuthal projection – a projection made by placing a sheet of paper against a transparent, lighted globe such
that the paper touches the globe at only one point
conic projection – a projection made by placing a paper cone over a lighted glove so that the axis of the cone
aligns with axis of the globe
polyconic projection – a series of conic projections used to increase the accuracy of the map
compass rose – a symbol on a map that indicates the cardinal directions
cardinal directions – the directions North, South, East and West
graphic scale – a printed line that has markings on it that are similar to those on a ruler
fractional scale – a scale on a map that uses a ratio
isobars – points on a weather map that share the same values
topographic map – a map that shows the surface features of Earth
contour interval – the difference in elevation between one contour line and the next
index contour – bold lines on a topographic map that represents every fifth contour line to make reading a map
easier
depression contours – depression on a topographic map which are closed-loop lines that have short, strait lines
perpendicular to the inside of the loop
geologic map – a map designed to show the distribution of geologic features
base map – a map that geologic maps are place on top of that provides surface features or roads used to help
identify the location of geologic units
geologic unit – a volume of rock of a given age range and rock type
contact line – a line on a map that indicates a place at which two geologic units meet
contact – the exact point where two geologic units meet
strike – the direction in which the beds run
dip – indicates the angle at which the beds tilt
soil map – maps constructed to classify, map and describe soils
parallel – any circle that runs east and west around Earth and that is parallel to the equator, a line of latitude
latitude – an angular distance north or south from the equator; expressed in degrees
meridian – any semicircle that runs north and south around Earth from the geographic North pole to the
geographic South pole; a line of longitude
longitude – the angular distance east or west from the prime meridian; expressed in degrees
remote sensing – the process of gathering and analyzing information about at object without physically being
in touch with the object
map projection – a flat map that represents a spherical surface
legend – a list of map symbols and their meanings
scale – the relationship between the distance shown on a map and that actual distance
isogram – a line on a map that represents a constant or equal value of a given quantity
topography – the size and shape of the land surface features of a region, including the relief
elevation – the height of an object above sea level
contour line – a line that connects points of equal elevation on a map
relief – the difference between the highest and lowest elevation in a given area