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# Models and dimensions of earth

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• Cartographer=map maker
• Cartographer=map maker
• ### Models and dimensions of earth

1. 1. Models of the EarthModels of the Earth
2. 2. Created by L. ZimmermanCreated by L. Zimmerman Introduction to MapsIntroduction to Maps Maps are an extremely useful tool forMaps are an extremely useful tool for many science and non-sciencemany science and non-science disciplines.disciplines. They provide “pictures” ofThey provide “pictures” of areas/regions/land surfaces!areas/regions/land surfaces! Correct interpretation can tell you MANYCorrect interpretation can tell you MANY things!things! – MINGOMINGO!!
3. 3. Created by L. ZimmermanCreated by L. Zimmerman Location on EarthLocation on Earth The earth is a sphere, soThe earth is a sphere, so how do we describe where ahow do we describe where a point is on its surface?point is on its surface? The most common way toThe most common way to locate points on the surfacelocate points on the surface is by basic, geographicis by basic, geographic coordinates: latitude andcoordinates: latitude and longitude.longitude. These coordinates valuesThese coordinates values are measured in degrees,are measured in degrees, and represent angularand represent angular distances calculated from thedistances calculated from the center of the Earth.center of the Earth.
4. 4. Created by L. ZimmermanCreated by L. Zimmerman Shape of the EarthShape of the Earth  Earth is mostEarth is most accuratelyaccurately described as andescribed as an oblate spheroidoblate spheroid (almost a sphere).(almost a sphere). Flattened at theFlattened at the polespoles 1.1. Bulges at theBulges at the equatorequator NPSP
5. 5. Created by L. ZimmermanCreated by L. Zimmerman Determining Earth’s ShapeDetermining Earth’s Shape 1.1. Observation of the North Star, Polaris.Observation of the North Star, Polaris. – Altitude is theAltitude is the heightheight, measured in, measured in degreesdegrees above the horizon of the observer.above the horizon of the observer. – The altitude of Polaris changes as anThe altitude of Polaris changes as an observer moves north or south (in theobserver moves north or south (in the Northern hemisphere); this is because EarthNorthern hemisphere); this is because Earth isis sphericalspherical and its surface isand its surface is curvedcurved..
6. 6. Created by L. ZimmermanCreated by L. Zimmerman LatitudeLatitude Altitude ofAltitude of PolarisPolaris 00oo 00oo 9090oo 9090oo 6565oo 6565oo d. Summary: The altitude of Polaris (above the horizon) is equal to the latitude of the observer on the globe.
7. 7. Created by L. ZimmermanCreated by L. Zimmerman Locating the North Star -Locating the North Star - of course youof course you would need to be in thewould need to be in the NorthernNorthern hemisphere!hemisphere! •The North Star is located at the end of the handle of the Little Dipper. •The North Star always points in the direction of True North. For this reason it has been used as and aid to navigation for many centuries.
8. 8. Finding LocationsFinding Locations on the Earthon the Earth There are three main reference points:There are three main reference points: EquatorEquator NorthNorth andand South Geographic PolesSouth Geographic Poles
9. 9. Latitude (parallels)Latitude (parallels) Describe positionsDescribe positions NorthNorth andand SouthSouth of theof the equator. Parallels runequator. Parallels run easteast toto westwest around thearound the world.world. Parallels are measure inParallels are measure in degreesdegrees fromfrom 00 toto 9090.. Those that are above the equator are labeledThose that are above the equator are labeled NorthNorth; those below are labeled; those below are labeled SouthSouth.. Each degree of latitude consists of 60 equalEach degree of latitude consists of 60 equal parts calledparts called minutesminutes.. o Each minute is divided intoEach minute is divided into 60 seconds60 seconds Example: 38Example: 38oo 53’ 51”53’ 51”
10. 10. Created by L. ZimmermanCreated by L. Zimmerman
11. 11. Longitude (meridians)Longitude (meridians) Describes positionsDescribes positions EastEast andand WestWest of the Primeof the Prime Meridian. Meridians runMeridian. Meridians run northnorth andand southsouth around thearound the world.world. The 0The 0oo meridian is called themeridian is called the Prime MeridianPrime Meridian and runsand runs directly throughdirectly through Greenwich, EnglandGreenwich, England.. LocationsLocations easteast of Prime Meridian have longitudesof Prime Meridian have longitudes betweenbetween 0 and 1800 and 180oo EE. Locations west of the Prime. Locations west of the Prime Meridian have longitudes betweenMeridian have longitudes between 0 and 1800 and 180oo WW.. Longitude can also be broken down intoLongitude can also be broken down into minutesminutes andand secondsseconds..
12. 12. Created by L. ZimmermanCreated by L. Zimmerman
13. 13. Great Circles & Finding DirectionGreat Circles & Finding Direction Great circles are used in navigation, generally byGreat circles are used in navigation, generally by pilotspilots. A great circle is any circle that. A great circle is any circle that dividesdivides the globe in halvesthe globe in halves.. Geomagnetic PolesGeomagnetic Poles – points on Earth directly– points on Earth directly above imaginary magnetsabove imaginary magnets Magnetic declinationMagnetic declination – angle between direction– angle between direction of geographic poles and the compass needleof geographic poles and the compass needle True NorthTrue North – the direction of the geographic North– the direction of the geographic North PolePole
14. 14. Mapping the Earth’s SurfaceMapping the Earth’s Surface CartographyCartography – science of map making– science of map making MapsMaps – flat representations of Earth– flat representations of Earth The best representation of earth is aThe best representation of earth is a globeglobe.. No matter what type of map is made, someNo matter what type of map is made, some portion is always distorted.portion is always distorted. CartographersCartographers work to minimize the effects of thesework to minimize the effects of these distortions.distortions.
15. 15. Reading a MapReading a Map LegendLegend - list of symbols and their meanings- list of symbols and their meanings ScaleScale – indicates the relationship (a ratio)– indicates the relationship (a ratio) between the distances on the map and thebetween the distances on the map and the actual distanceactual distance
16. 16. Created by L. ZimmermanCreated by L. Zimmerman D. Position Characteristics –D. Position Characteristics – How can theHow can the characteristics of a position be measured and described?characteristics of a position be measured and described? 1)1) Isolines –Isolines – lineslines on a f ield mapon a f ield map t hatt hat connectconnect point s ofpoint s of equalequal value.value.
17. 17. Created by L. ZimmermanCreated by L. Zimmerman Examples of isolines:Examples of isolines: a)a) Contour LinesContour Lines (Topogr aphic) – lines t hat(Topogr aphic) – lines t hat connect point s of equalconnect point s of equal ElevationElevation.. b)b) IsobarsIsobars – lines t hat connect point s of equal– lines t hat connect point s of equal pressurepressure. Found on a. Found on a weather mapweather map.. c)c) IsothermsIsotherms – lines t hat connect point s of– lines t hat connect point s of equalequal temperaturetemperature. Found on a. Found on a weatherweather mapmap.. d)d) IsosurfaceIsosurface – A model that represents field– A model that represents field characteristics in 3-D.characteristics in 3-D.
18. 18. Topographic MapsTopographic Maps http://www.rollanet.org/~conorw/cwome/hahatonka_topo_map.jpg
19. 19. Features of Topographic MapsFeatures of Topographic Maps ElevationElevation – height above sea level– height above sea level Sea levelSea level – point between the highest and lowest tide– point between the highest and lowest tide levels (elevation at sea level = 0)levels (elevation at sea level = 0) Contour linesContour lines – used to show elevation and connect– used to show elevation and connect all points on the map with equal elevationall points on the map with equal elevation Contour intervalContour interval – difference in elevation between– difference in elevation between one contour line and the nextone contour line and the next ReliefRelief – difference in elevation between the highest– difference in elevation between the highest and lowest pointsand lowest points Index contourIndex contour – every 5– every 5thth line is BOLD and itsline is BOLD and its elevation is labeledelevation is labeled
20. 20. Created by L. ZimmermanCreated by L. Zimmerman Contour Lines: Connect all points on a map that have the same elevation above sea level.
21. 21. Topographic MapsTopographic Maps Colors on topographic maps:Colors on topographic maps: – Blue:Blue: Water (rivers, lakes, streams, etc.)Water (rivers, lakes, streams, etc.) – Green:Green: VegetationVegetation – Red:Red: Contour LinesContour Lines
22. 22. Topographic MapsTopographic Maps There are many symbols used on theThere are many symbols used on the map. These are explained in themap. These are explained in the legendlegend..
23. 23. Topographic MapsTopographic Maps Contour lines spaced close together indicate aContour lines spaced close together indicate a steepsteep slope.slope. Contour lines spaced far apart indicate aContour lines spaced far apart indicate a gentlegentle slopeslope.. Contour lines that form a closed loop indicate aContour lines that form a closed loop indicate a hillhill.. Contour lines that form a circle with dashed linesContour lines that form a circle with dashed lines indicate a depressionindicate a depression.. V-shaped contour lines indicate aV-shaped contour lines indicate a valleyvalley and the “V”and the “V” will pointwill point downstreamdownstream. (Rivers flow DOWNHILL). (Rivers flow DOWNHILL)
24. 24. Topographic MapsTopographic Maps Depression (shown using hachures)
25. 25. Topographic MapsTopographic Maps Advanced TechnologyAdvanced Technology: Gives us the: Gives us the ability to measure and analyze theability to measure and analyze the physical properties of Earth with muchphysical properties of Earth with much greater precision.greater precision. – Examples:Examples: GPSGPS andand Weather satellitesWeather satellites..
26. 26. Created by L. ZimmermanCreated by L. Zimmerman Features of Topographic Maps Relationship between 3D and 2D representation 3D view 2D view
27. 27. Created by L. ZimmermanCreated by L. Zimmerman Contour lines Relationship between topographic features and contour lines
28. 28. Created by L. ZimmermanCreated by L. Zimmerman Topographic Profile
29. 29. Created by L. ZimmermanCreated by L. Zimmerman The RESULT – a 3-D pictureThe RESULT – a 3-D picture
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