Models of the Earth

Latitude Also called parallelsAlso called parallels Measured in degrees north or southMeasured in degrees north or south Equator is the invisible line that divides the earth into the Northern and Southern hemisphereEquator is the invisible line that divides the earth into the Northern and Southern hemisphere Poles are 90º North and SouthPoles are 90º North and South Each degree is divided into 60 minutes and each minute is divided 60 seconds.Each degree is divided into 60 minutes and each minute is divided 60 seconds. Each minute is 1.85km.Each minute is 1.85km.

Latitude and Polaris Aim: What is the relationship between latitude and Polaris?

Polaris Also called the North Star (brightest). Always in the northern nighttime sky. Is located very close to the North Celestial Pole.

* Polaris * Polaris' altitude, or height above the horizon, is equal to an observer's latitude.altitude

As you move north and your latitude increases, Polaris' altitude also increases. But if you pass south of the equator, the North Star will no longer be visible and you'll need to check a map to find your latitude!

Longitude Called meridiansCalled meridians Measured in degrees East and WestMeasured in degrees East and West Prime meridian is invisible line that passes through Greenwich, England and near the International Date line on the opposite side of the EarthPrime meridian is invisible line that passes through Greenwich, England and near the International Date line on the opposite side of the Earth Lines run between 0º to 180º East and West.Lines run between 0º to 180º East and West. Each degree can be divided into 60 minutes and each minute is divided into 60 seconds.Each degree can be divided into 60 minutes and each minute is divided into 60 seconds. Each degree equals 111 km at the equator and eventually goes to zero at the poles.Each degree equals 111 km at the equator and eventually goes to zero at the poles.

Difference between geomagnetic and geographic poles The angle between the geomagnetic and the geographic poles is called magnetic declination.

GPS Uses signals from 3 different satellites (of a total of 24) to determine location

Mapping the Earth’s Surface Cartographers are map makers Data is gathered from field surveys to remote sensing Globes are the best because flat maps distort areas of the Earth.

Technological Advances in Map Making Air photos and satellite images relate to actual 3-D landforms Satellite technology gives an even broader view of Earth by gathering data from broad areas of Earth’s surface.

Cylindrical or Mercator Projection Has a perfect grid systemHas a perfect grid system Distorts areas near the polesDistorts areas near the poles Good for small area mapsGood for small area maps

Azimuthal or Gnomonic Projections Made by placing a piece of paper on a globeMade by placing a piece of paper on a globe Little distortion at the point of contact but increases as you move from that pointLittle distortion at the point of contact but increases as you move from that point Used by navigatorsUsed by navigators

Conic Projections Made by placing a cone over a globeMade by placing a cone over a globe Areas near poles have least distortionAreas near poles have least distortion Small area maps are the bestSmall area maps are the best

Reading a Map Direction found on compassDirection found on compass Use the symbols in a legendUse the symbols in a legend Map scales for distance on the map verses the actual distanceMap scales for distance on the map verses the actual distance

Topographical Maps Show the surface features or topography of the landShow the surface features or topography of the land Contours lines are used to show elevationContours lines are used to show elevation Contour interval is the distance between each lineContour interval is the distance between each line Index contour are bolded lines that give the elevationIndex contour are bolded lines that give the elevation

7.5 minute quadrangle topographic map 1:24,000-scale

Lines close together indicates steep terrainLines close together indicates steep terrain Lines far apart indicates gradual changeLines far apart indicates gradual change V shape indicates valleys with a river flowing toward the open end of the VV shape indicates valleys with a river flowing toward the open end of the V Depressions are indicated by hachured linesDepressions are indicated by hachured lines

Drawing Topographical Maps

Gradient = Drop in elevation between 2 points Distance between two points 20 = 4 m/km 5

1. What is the contour interval for this map? 2. What is the distance between points E and F? 3. What direction does Cedar River flow? 4. What is the gradient between points D and E? 5. Which side of hill C has the steepest slope? 6. What is the elevation of the last depression line on hill B?

Now the Fun begins… read this map and tell me