INTRODUCTION TO PHYSICAL GEOGRAPHY: Chapter 1 The “spheres” of Earth Hydrosphere Lithosphere Atmosphere Biosphere  

The earth is elliptical. Which shape type is correct, and why? note: ellipticity exaggerated in photos!

Earth’s dimensions Figure 1.8

Geodesy: Earth Division Latitude “parallels”: 1 degree = 69 miles 60 minutes = 1 degree (1 minute = 1.15 miles) 1 nautical mile = 1.15 miles 1 second = 1/60 of 1 nautical mile Longitude: lines are not parallel, are called "meridians” -At equator only: 1 degree = 69 miles, but declines to zero at the poles

Latitude Figure 1.10

Longitude Figure 1.12

Lines of latitude to know: Equator (O°) starting point to number parallels Tropic of Cancer (23.5° N) Tropic of Capricorn (23.5° S) Arctic Circle (66.5° N) Antarctic Circle (66.5° S)

Important Meridians to know Greenwich or “Prime” (goes through England). Is starting point (0°) for numbering longitude International Date Line: (180° E&W) the place where new days start; is halfway around the world from Greenwich Meridian

Distance on a Globe Question: The shortest distance between two points is: a straight line A Great Circle Route All of the above Answer: c) A Great Circle Route is a circle formed by passing a plane through the exact center of a perfect sphere. Cuts earth into two equal sized pieces.

Great Circles and Small Circles Figure 1.13

MAPS The “perfect map” representation of the earth is a globe True maps are two dimensional: problem of representing a round earth surface on a flat one. The problem with globes is one of scale (example: how large would a globe have to be to include details of Monmouth, Oregon on it?)

Maps and Projections   Map – a generalized view of an area, as seen from above and reduced in size Projection – process of transforming the spherical Earth to a flat map

Properties of Maps Scale: ratio of the distance on the map to the actual distance of the transect that it represents. Examples 1:100 1:10,000 Which shows more detail? Area Shape impossible to preserve area and shape over an entire map

Skip Examples of Map Projections Read Chapter 1; see Appendix A. Ones to be able to recognize: Mercator (true shape), areas exaggerated at higher latitudes, useful for navigation Polar

Isoline Mapping uses lines of equal value Examples: Topographic maps: lines of equal elevation (appendix A-4) Isotherm maps: lines of = temperature (p. 94) Isohyet maps: lines of = precipitation (p. 191) mon. Isobar maps: lines of = pressure (p. 122)

Theoretical number of time zones of 1 hr. each: 24 Figuring out how many degrees of longitude should be in each time zone: Theoretical number of time zones of 1 hr. each: 24 Number of degrees in a circle: 360 360/24 ≈ 15 degrees average per zone Figure 1.23

The International Date Line: Where all New Days Begin Moving through time zones to the west, subtract 1 hour for each. (If it is 5 am in Wyoming, what time is it in the next time zone to the west?) As it turns midnight in the time zone of the IDL, the new day begins. At first, the new day is just in the 1st time zone, but 1 hr. later it spreads to the next zone to the west, and so on.

Prime Meridian and Standard Time Figure 1.14

Geographic Information Systems (GIS) GIS is defined as any system which facilitates the analysis of multiple layers of spatial data (maps of specific themes)

GIS System Figure 1.23