Chapter 3 Section 2 Notes
Mapping Earth’s Surface
- cartography – science of making maps
- cartographer – scientists who make maps
Data collected by field surveys and remote sensing are used
to make maps
- field survey – make measurements of the area
o plot information on a map
- remote sensing – the process of gathering and analyzing
information about an object without physically being in
touch with the object
o satellite images
o images from airplanes
Map Projections
- a flat map that represents a spherical surface
Cylindrical Projection
- a cylinder of paper is wrapped around a lighted globe
- meridians appear as straight lines
- outlines of continents, oceans and parallels are traced
- parallels and meridians form a grid
Azimuthal Projection
- a sheet of paper is placed on a lighted globe so that only
one point of the globe is being touched
- little distortion occurs at the point of contact
- unequal spacing between parallels causes a distortion in
both direction and distance
- great help to navigators in plotting routes used in air
travel
Conic Projections
- placing a paper cone over a lighted globe so that the axis
of the cone aligns with the axis of the earth
- the cone touches the globe along one parallel of latitude
- areas near the parallel are distorted least
- polyconic projections – a series of conic projections used
to increase the accuracy of mapping a number of
neighboring areas
Reading a Map
Directions on a Map
- maps are mostly drawn with the top of the map facing
north
- parallels run from side to side
- meridians run from top to bottom
- compass rose – a symbol that indicates the cardinal
directions(north, south, east, west)
Symbols
- symbols are used for features on a map such as cities,
roads and rivers
- legend – a list of map symbols and their meanings
Map Scales
- a map must be drawn to scale to be accurate
- scale – the relationship between the distance shown on a
map and the actual distance
- graphic scale – printed line that has markings on it that
are similar to those on a ruler
- fractional scale – a scale that uses a ratio
Isograms
- a line on a map that represents a constant or equal value
of a given quantity
- used to plot many types of data (i.e., atmospheric
pressure on a map)
- commonly used to show areas that similar measurements
of precipitation, temperature, gravity, magnetism,
density, elevation or chemical composition