Create Presentation
Download Presentation

Download Presentation
## PHYSICAL GEOGRAPHY Maps

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**PHYSICAL GEOGRAPHYMaps**Chapter 2 C.J. Cox**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Key Terms**• Map: a flat representation of a globe • Cartography - the art and science of mapmaking**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**4 KEY PROPERTIES OF MAPS**Shape Area (size) Distance Direction**Key Terms**• Conformal Map - shows correct shape • Equal Area Map - shows correct area • Rhumb Line - line shows correct direction • Great Circle - the largest circle that can be drawn on a globe. This circle divides the globe into two halves and is the shortest distance between any two points.**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Key Terms**• Great Circle - the largest circle that can be drawn on a globe. This circle divides the globe into two halves and is the shortest distance between any two points.**Key Terms**• Rhumb Line - line shows correct direction**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Map Projections**• Projection: The system used to transfer locations from Earth’s surface to a flat map. • A projection of an image onto another surface • either a cylinder, a flat plane or a cone • 3 basic types of projections • cylindrical projection • planular projection (also known as azimuthal) • conical projection**CYLINDRICAL PROJECTION**used by navigators to show direction Meridians run north & south Parallels run east & west**Cylindrical Maps**are conformal maps they conform to the correct shape**CONICAL PROJECTION**used for Mid-Latitude Maps True Area (between the standard parallels) Also referred to as equal area maps**PLANULAR PROJECTION**used by pilots Shows Great Circle Routes**ROBINSON PROJECTION**Compromise projection**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range (Survey System) • Contour Maps • Remote Sensing**SCALE**• Scale: the relationship between units on the map and actual distance on the ground • Written Scale: one inch equals one mile • Linear Scale: |---------|---------|----------| • or Graphic Scale • Representative Fraction: 1:63,360**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Latitude & Distance**• Earth’s Circumference 24,840 miles • 24,840 divided by 360 degrees of a circle • One degree equals 69 miles • One degree can be divided into 60 parts or minutes • 69 miles divided by 60 equals 1.15 miles • Therefore one minute equals 1.15 miles • One minute is a nautical mile (1.15 miles)**Latitude & Distance**• One minute can be further divided into 60 seconds • One minute or 1.15 miles divided by 60 equals 102 feet • Therefore one second equals 102 feet • WHAT IS THE DISTANCE SHOWN ON A 15 MINUTE MAP?**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Magnetic North**• The earth holds a mass of liquid, fluid mass of iron around the solid inner core • This generates a powerful magnetic field within the earth that is generated into outer space**True North = Geographic North**or North Pole Magnetic North = where the compass points to 76N 102 W**Declination - the difference**between magnetic and geographic north 17 E**Terms**• Isogons - lines connecting points of equal magnetic variation away from the geographic north • Agonic Line - points along a line where there is no magnet variation or declination from the geographic north**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Township & RangePublic Land Survey System**• A rectangular grid system adjusted to the geographic grid • East west lines are surveyed and coincide with parallels of latitude • prominent parallel is known as the base line • Vertical divisions are called ranges • prominent meridians are called principal meridians**Chapter 2 Concepts**• Key properties of maps • Great Circles • Map Projections • Scale • Latitude & Distance • Longitude & Time • Magnetic North • Township & Range ( Survey System) • Contour Maps • Remote Sensing**Contour Maps**• Maps showing lines that indicate locations of equal elevations