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EARTH - MAP RELATIONSHIPS

EARTH - MAP RELATIONSHIPS. The Size and Shape of the Earth. EARTH - MAP RELATIONSHIPS. The Size and Shape of the Earth. Globe. Flat Map. EARTH-MAP RELATIONSHIPS. 1. Definition of Geodesy 2. Shapes of the Earth 3. Geographic Coordinates 4. The Graticule 5. Geodetic Control Points.

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EARTH - MAP RELATIONSHIPS

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  1. EARTH - MAP RELATIONSHIPS The Size and Shape of the Earth

  2. EARTH - MAP RELATIONSHIPS The Size and Shape of the Earth

  3. Globe

  4. Flat Map

  5. EARTH-MAP RELATIONSHIPS 1. Definition of Geodesy 2. Shapes of the Earth 3. Geographic Coordinates 4. The Graticule 5. Geodetic Control Points

  6. EARTH-MAP RELATIONSHIPS 1. Definition of Geodesy 2. Shapes of the Earth 3. Geographic Coordinates 4. The Graticule 5. Geodetic Control Points

  7. 1. GEODESY • The science concerned with determining the size and shape of the Earth • Establishment and maintenance of a global three-dimensional network of geodetic control points. • Measuring Geodynamic Phenomena (Geodynamics) • To Determine: • The exact positions of points on the earth’s surface • The size and shape of the earth • The variations in terrestrial gravity

  8. EARTH-MAP RELATIONSHIPS 1. Definition of Geodesy 2. Shapes of the Earth 3. Geographic Coordinates 4. The Graticule 5. Geodetic Control Points

  9. 2. THE SHAPES OF THE EARTH • SPHERE • ELLIPSE • ELLIPSOID • GEOID • GEOID SEPARATION

  10. THE SHAPES OF THE EARTH • SPHERE: • A body of space bounded by one surface all points of which are equally distant from a point (center). • Constant radius

  11. THE SHAPES OF THE EARTH • ELLIPSE: The path of a point the sum of whose distances from two fixed points (the foci) is constant

  12. THE SHAPES OF THE EARTH • ELLIPSE: Flattening:

  13. THE SHAPES OF THE EARTH • ELLIPSE: Flattening: World Geodetic System ‘84 WGS ‘84 a = 6,371,137 meters b = 6,356,752.2142 meters f = 298.25722

  14. THE SHAPES OF THE EARTH • ELLIPSOID (SPHEROID): Surface developed by rotating an ellipse about its minor axis (oblate spheroid - tomato shaped) or major axis (prolate spheroid - cigar shaped).

  15. THE SHAPES OF THE EARTH • ELLIPSOID (SPHEROID):

  16. THE SHAPES OF THE EARTH • GEOID: The equipotential surface of the Earth’s gravity field which coincides with the surface the oceans would have if they were motionless and affected only by the Earth’s gravity field.

  17. THE SHAPES OF THE EARTH • GEOID: An exaggerated view of the geoid in relation to the ellipsoid and the sphere

  18. GEOID ‘96A view of the Continental US

  19. GEOIDA view of the world

  20. GEOID SEPARATION • GEOID SEPARATION: The perpendicular distance from the reference ellipsoid to the geoid. + The Geoid is above the Ellipsoid - The Geoid is below the Ellipsoid WGS ‘84 Ellipsoid and Geoid ‘96: Maximum separation worldwide  100 meters In Continental U.S.  - 20 meters

  21. Geoid Height = Geoid Separation  Geoid Undulation

  22. THREE EARTH SURFACES Geoid Height

  23. GEOID SEPARATION

  24. “The Four Corners of the Earth” 1 2 4 3

  25. GEOID UNDULATION

  26. Ellipsoid Datum Fit with Geoid

  27. EARTH SURFACES

  28. GEOID - ELLIPSOID RELATIONSHIP STATION “DURHAM 1943” : • Located behind Kendall Hall • Geoid Height (Geoid 93 Model) = - 27.184 meters •  10 cm (3’ by 3’ Lat., Long. Grid) ( 100 km) • Geoid ‘96:  3 cm (1) (2’ by 2’ Lat., Long.) • Geoid ‘99: • Elevation 106.46’ (above “mean sea level”)

  29. GEOID - ELLIPSOID RELATIONSHIP STATION “DURHAM 1943” :

  30. GEOID - ELLIPSOID RELATIONSHIP STATION “DURHAM 1943” :

  31. GEOID - ELLIPSOID RELATIONSHIP

  32. EARTH-MAP RELATIONSHIPS 1. Definition of Geodesy 2. Shapes of the Earth 3. Geographic Coordinates 4. The Graticule 5. Geodetic Control Points

  33. 3. GEOGRAPHIC COORDINATES • LATITUDE:  • LONGITUDE: 

  34. 3. GEOGRAPHIC COORDINATESLatitude and Longitude

  35. 3. GEOGRAPHIC COORDINATES • LATITUDE:  The north-south position on the Globe “A Parallel”

  36. 3. GEOGRAPHIC COORDINATES • LONGITUDE:  The east - west position on the Globe “AMeridian”

  37. Orthogonal vs. Geographic Coordinates Ellipsoid Sphere Geographic Coordinates Orthogonal Coordinates “Authalic” Coordinates

  38. 3a. GEODETIC COORDINATES • LATITUDE Angle formed by a line from the equator to the center of the earth, and a second line perpendicular to ellipsoid’s surface at your location. Point

  39. 3a. GEODETIC COORDINATES • LONGITUDE Angle between a “prime” meridian and your “local” meridian. Point

  40. REVIEW OF TOPICS EARTH-MAP RELATIONSHIPS 1.Definition of Geodesy 2. Shapes of the Earth 3. Geographic Coordinates 4. The Graticule 5. Geodetic Control Points

  41. EARTH-MAP RELATIONSHIPS 1. Definition of Geodesy THE SCIENCE CONCERNED WITH DETERMINING THE SIZE AND SHAPE OF THE EARTH 2. Shapes of the Earth SPHERE, ELLIPSE, ELLIPSOID, GEOID, GEOID SEPARATION 3. Geographic Coordinates LATITUDE, LONGITUDE: GEOGRAPHIC (AUTHALIC) VS. GEODETIC, X,Y,Z

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