World Natural Environments

Introductory conceptsIntroductory concepts

1.1. Earth-sun relationshipsEarth-sun relationships

2.2. Geographic gridGeographic grid

3.3. Map useMap use

1.1. Earth-sun relationshipEarth-sun relationship

Significance:Significance: seasonal distribution of solar seasonal distribution of solar

radiationradiation general circulation of atmosphere & general circulation of atmosphere &

oceansoceans Spatial distribution of climate regions Spatial distribution of climate regions

& vegetation types& vegetation types

Plane of the ecliptic

Axial Inclination

Axial Parallelism

2. Geographic grid2. Geographic grid

Significance:Significance: Provides system for locating featuresProvides system for locating features Longitude provides basis for time Longitude provides basis for time

zoneszones

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

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

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

(x, y)

(x, -y)

(-x, y)

(-x, -y)

Where x = longitude and y = latitude

3. Map use3. Map use

Uses of maps:Uses of maps: Aids to location, navigationAids to location, navigation Portray spatially distributed Portray spatially distributed

informationinformation

Thematic mapsThematic maps

Isopleth mapsIsopleth maps

Choropleth maps: Choropleth maps:

Isopleth mapsIsopleth maps

Constructed from Constructed from point datapoint data

Extrapolated to Extrapolated to lines or areaslines or areas

Displays Displays continuous datacontinuous data

Choropleth mapsChoropleth maps Constructed from area-based data Constructed from area-based data

Boundaries of areas may be natural or man-made Boundaries of areas may be natural or man-made (defined)(defined)

Displays discrete dataDisplays discrete data

Exercise 1Exercise 1