18 A. Paper Maps are Flat 2-Dimensional Representations of Earth’s Surface Problems:Not as accurate as a 3-D Globe modelEarth’s features become distorted (they don’t look right)
19 B. Map MakingSurveyorsUse distance and elevation information from known points to create mapsKnown points of elevation are called:bench marks, metal stakes placed in stone and marked with the location and elevationAerial (from the sky)photographyalso helps make maps
22 Modern surveyors use:CompassInfrared theodolite& GPS
23 C. Map ProjectionsCartographers (map makers) illustrate world maps as a projection to reduce distortionMap projection – transferring a curved surface (the Earth, sphere) to a flat one (the map).Common map projections: Mercator, Gnomonic (polar), and (Poly)conic
24 I. Mercator Projection Map The mercator map projection shows the view of Earth as if a large cylinder of paper had been wrapped around the globe. This is the most common type of projection
25 Mercator Projection Map -Disadvantage Major distortion effects near the poles (land looks larger than what it really is)+Advantage Indicates true directions as straight lines of latitude and longitude, makes a rectangular grid pattern
26 II. Gnomonic or polar Projection Map A gnomonic or polar projected map is created as if a piece of paper had been placed on a point on the Earth.
27 III. (Poly)Conic Projection Map The (poly)conic map projection shows the view of Earth as if a large paper cone had been wrapped around the globe.This type of map is useful for mapping areas in the middle latitudes.
28 Identify the type of map projection. Write the name of the type of projection in your notes
29 Review: What type of halves is the Earth divided into? North-South Hemispheres are separated by the imaginary line called the EquatorEast-West Hemispheres are separated by imaginary lines called the Prime Meridian (Greenwich Meridian) and the International Date Line
30 Latitude and Longitude Grid of imaginary lines placed over Earth Every location on the Earth has a specific latitude and longitude “address.”
31 LatitudeLatitude lines circle the Earth horizontally, parallel to the Equator (0 Degrees)Latitude is measured in Degrees North or South of the equator (0-90 Degrees)HHS is at 37° North Latitude
32 LongitudeLongitude lines are half-circles that extend vertically between the polesLongitude is measured in Degrees East or West of the Prime Meridian (0-180 Degrees)HHS is at 78° West Longitude
33 D. How do you know the size of landforms or the distance between cities on a map? The map scale indicates how the map’s features and distances compare with the actual EarthThe comparison is given as a ratio:1:24,000
34 Map Scale as a Ratio1 : 24,000 means that 1 map unit equals = 24,000 units on Earth
35 E. How do you determine direction on a map? Usually, most modern maps place North at the topCompass Rose indicates directionGeographic North vs Magnetic NorthAre they the same?No, because…the Earth is tilted on its axis
36 Earth Observing System The satellites in the Earth Observing Systems (EOS) will contain sensors to monitor global climate change.
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