Post on 17-Dec-2015
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