1. World Natural Environments

2. Introductory concepts
Earth-sun relationships
Geographic grid
Map use

3. Earth-sun relationship
Significance:
seasonal distribution of solar radiation
general circulation of atmosphere & oceans
Spatial distribution of climate regions & vegetation types

4. Plane of the ecliptic

5. Axial Inclination

6. Axial Parallelism

8. 2. Geographic grid Significance: Provides system for locating features
Longitude provides basis for time zones

10. Meridians of Longitude
Measures angular distance east or west
Reference point is the prime meridian through Greenwich, England
Values range from 0 – 180o
Longitude is the x in an (x,y) coordinate pair

11. Parallels of Latitude Measures angular distance north or south
Reference point is the equator
Values range from 0 – 90o
Latitude is the y in an (x,y) coordinate pair

12. Latitude / Longitude
Usually measured in degrees, minutes, seconds (e.g. 90o 30’ 36”)
60 seconds / minute
60 minutes / degree
so, 3600 seconds / degree
May be expressed in decimal degrees
90o 30’ 36” = 90.51o

13. (-x, y)
(x, y)
(-x, -y)
(x, -y)
Where x = longitude
and y = latitude

14. 3. Map use Uses of maps: Aids to location, navigation
Portray spatially distributed information

19. Thematic maps
Isopleth maps
Choropleth maps:

20. Isopleth maps Constructed from point data
Extrapolated to lines or areas
Displays continuous data

21. Choropleth maps Constructed from area-based data
Boundaries of areas may be natural or man-made (defined)
Displays discrete data

22. Exercise 1