MAPPING

VOCABULARY: globe, map; oblate ellipsoid, N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, NNW, grid system, degree, minute, second, latitude, longitude, parallel, equator, North Pole, South Pole, meridian, prime meridian, international date line, cartography, projection, equivalence, conformality, tangency, cylindrical projection, Mercator projection, conical projection, azimuthal projection, planar projection, map essentials, scale, verbal, graphic, representative fraction (RF) or fractional, small scale, large scale, legend, choropleth map, isopleth or isarithmic map, isopleth interval, topographic map, contour line, contour interval, USGS, model, remote sensing, aerial photograph, stereoscopic pair, GIS, mental map



globe--spherical representation of the earth
map--representation of the earth's surface on a flat sheet
earth is an oblate spheroid, prolate ellipsoid, oblate ellipsoid--flattened at the poles and bulging a little south of the equator

compass directions: words and numbers--See The Compass Rose and Azimuths

grid system--set of intersecting lines

Summary of latitude and longitude: A circle contains 360 degrees (°). A degree is divided into 60 minutes ('), and a minute is divided into 60 seconds ("). Latitude measures the number of degrees north or south of the equator which has a latitude of 0. The highest latitude possible is 90. All latitudes except for the equator must be designated either north or south of the equator. Except for exactly at the poles, a latitude coordinate designates a parallel around the earth. The longitude coordinate is also needed then to designate one particular point on the earth's surface. Longitude measures the number of degrees east or west of the prime meridian which runs through Greenwich, England. The prime meridian has a longitude of 0. Halfway around the globe is the 180 meridian which is the highest longitude possible. All other longitudes must be designated either east or west of the prime meridian. All meridians merge at the poles so exactly at the poles no longitude can be given; the longitude of the poles is left blank. It is required that latitude be given before longitude.

PRACTICE EXERCISE on latitude and longitude map from class--View the map and the answers.

360 degrees in a circle; 24 hours in a day; = 15 degrees per hour for size of a time zone
central meridians are multiples of 15

cartography--the science of map making
need to use a projection--means of representing a curved surface on a flat sheet

characteristics of projections

  • equivalence--equal area relations throughout the map
  • conformality--shapes are truly represented

  • line or point of tangency--where globe and paper touch, the location of least distortion
    some types of projections:
  • cylindrical--includes the Mercator which is the only conformal
  • conical--includes the Lambert conic conformal (common for midlatitudes)
  • azimuthal--tangent at center of projection (commonly to show poles)
  • planar--projected onto a plane
  • many others
  • map essentials: scale, legend, direction, title, date

    scale--reduction--shows size relationship