1. Mapping Cont.

2. Cartography Cartography is the science of map making
Early maps were usually limited to a very small area and had very little detail compared to modern maps
Limited technology
Limited understanding of the earth
Humans had no need/use for maps beyond their particular local area

3. Technology
Technological advances have dramatically changed cartography
Surveying equipment
Surveyors use geometry and
trigonometry to calculate
and accurately map small areas

4. Remote Sensing Use of satellites to measure and map the Earth
Landsat Satellite
First launched in 1972
Landsat 7 was launched in 1999
Passive system
Receives reflected wavelengths
of energy emitted by Earth’s
surface
¼ of the Earth’s
landmasses are mapped
every 16 days

5. LandSat
These satellites take pictures of Earth’s surface using different wavelengths of light.
The images can be used to make maps of snow cover over the United States or to evaluate the impact of forest fires.

6. Topex/Poseidon Satellite
Topex = Topography experiment
Launched in 1992, stopped in 2006
The first satellite dedicated solely to the study of the oceans
Active system
Uses radar
to map changes

7. Jason series The follow up to Topex/Poseidon
Jason – 1 launched in 2001
Jason – 2 launched in 2008
Accurate to 3.3 cm

8. Sound Navigation and Ranging
SONAR
SOund Navigation And Ranging
Used to measure and map the seafloor
Produce bathymetry charts
Study of underwater depth of lake or ocean floors

9. Global Positioning Systems (GPS)
First developed in 1960 by the mighty US Navy 5-satellite system that could provide a fix once per hour
1983 President Reagan removed restrictions making GPS available to the public for free
By 1994, 24 satellites were in use
Receiver calculates the user’s precise
latitude and longitude by processing
signals emitted by multiple satellites

10. GPS cont.
In 2004 all restrictions were removed, greatly improving accuracy for public use
We now have 32 operational GPS satellites providing positioning, navigation, and timing information

11. Types of Maps Maps are flat models of a 3-D object
Any map of the Earth is going to have some distortion because a map is a flat representation of a curved surface.
Map projection made by transferring points and lines on a globe’s surface onto a sheet of paper

12. Conic Projection
Map is projected onto a cone. The cone touches the globe along a single line of latitude.
Good for mapping small areas, but the area around the poles is distorted.

14. Gnomonic Projection Map is projected onto a flat piece of paper.
The paper touches the globe at a single point.
Good for plotting long distance trips, but the direction and distance between land masses is distorted.

15. Gnomonic Projection

16. Mercator Projection
This map shows lines of latitude and longitudes as straight, parallel lines
Good for navigation, but the landmasses near the poles are distorted
Example – Greenland appears much bigger than Australia, but just the opposite is true.

17. Mercator Projection

18. Topographic Maps
Topo maps show change in elevation (height above sea level)
Contour lines (concentric circles) connect points of equal elevation
Contour lines never intersect or cross
Contour lines never dead end
Contour lines never fork or split

19. Contour Lines Contour lines can be more than just elevation
Temperature
Precipitation
Snow cover is frequently shown as a contour-line map
Air Moisture
Wind
Magnetism

20. Index Contours Index contours have their elevations written on them
Contour interval is the difference in elevation between one contour line and the next one.

21. Contour Lines cont.
Contour lines spread far apart indicate a gentle slope
Contour lines spaced very closely together represent a steep slope

22. Depression Contours
Depression contours show a decrease in elevation

23. Map Legends
Topographic maps and most other maps include both human-made and natural features located on Earth’s surface
Represented by symbols
Black dotted lines for trails
Solid red lines for highways
Small black squares and rectangles for buildings
Map legend explains what the symbols represent

24. Map Scales
Ratio between distances on a map and actual distances on the surface of Earth
3 types of scales
Verbal Scales – expresses distance as a statement
Ex. One centimeter is equal to one kilometer
Graphic Scales – consists of a line that represents a certain distance. Line is broken down into sections with each section representing a distance on Earth’s surface.
Fractional Scale – expresses distance as a ratio such as 1:63500
Meaning that one unit on the map represents 63,500 units on Earth’s surface