llhammon Maps and Map Skills

llhammon Maps and Map Skills

Kinds of Maps 1. General Reference Maps 1. Thematic Maps Provide the reader general information about an area or place. Provide more specific information about an area or place than general reference maps.

General reference

Thematic Map

Globe is a better model of Earth than a map, but a globe has disadvantages that a map does not have

Reading Maps 1. Map Parts 2. Map orientation Title Legend or Key Grid System Direction Scale This has to do with direction

Compass Title Scale

Large Scale and Small Scale Maps 1. large-scale map 2. small-scale map Small Area = Large Scale Large Area = Small Scale shows a small area such as a neighborhood street in great detail. shows a large area such as a country or a continent in comparatively lesser detail.

Large Scale Small Scale Small Area = Large Scale Large Area = Small Scale

Compass Is used to orient a map toward north

Latitude and Longitude

Latitude The set of lines crossing the Earth s surface horizontally, Circling east and west. Each line of latitude is always an equal distance from the next. They are also known as parallels. All latitude lines are parallel to each other.

Longitude - A set of lines that run vertically along Earth s surface from the North Pole to the South Pole

Global Grid When lines of latitude and longitude cross a grid is formed. The grid is used to located certain places on earth

Each line has an Identifying number called degrees, or parts of a circle. (41 0 ) Degrees, can be further divided into minutes, or parts of a degree. There are 60 minutes, or parts of a degree. (10 ) Minutes can be divided into even smaller parts called seconds. There are 60 seconds in each minute. (10 ) 41 0 10 10 41 0 Degrees Minutes Seconds 10 10

Direction Cardinal directions Intermediate directions north, south, east, west. -Northeast -Northwest -Southeast -Southwest

Using Latitude & Longitude to Lines of latitude Locate Places are numbered based on how far north or south they are from an imaginary line called the equator This line circles the Earth exactly halfway between the NP and SP. equator s latitude The degree is 0 0. There are 90 degrees between it and each of the poles. Area 0 between the equator and NP is north latitude (22 N) Area 0 between the equator and SP is south latitude (22 S)

Using Latitude & Longitude to Locate Places Lines of longitude Prime Meridian s longitude are numbered based on how far east or west they are from another imaginary line. degree is 0 0. Area 0east of the PM is known as east longitude. (120 E) Area 0west of the PM is known as west longitude. (120 W)

Prime Meridian & International Date Line prime meridian does not circle the globe as the equator does. PM runs from the NP to SP international date line. Runs from NP to SP 180 0 on the other side of the globe

Hemispheres The earth can be divided into halves. Each of these halves is called a hemisphere.

Hemispheres at the Equator The ½ north of the equator is called the northern hemisphere The ½ south of the equator is called the southern hemisphere

Hemispheres at Prime Meridian and International Date Line Earth can also be divided into hemispheres at the circle formed by the prime meridian and International date line The ½ east of the prime meridian is called the eastern hemisphere. The ½ west of the prime meridian is called the western hemisphere.

Making Maps Gathering Information Problem of Distortion Map Properties Map Projections Cartographers (Mapmakers)

Gathering Information Surveying Aerial Photography (Air Planes) Remote Sensing (Satellites)

Problem of Distortion Features are stretched to put Earth s information onto a map.

Map Properties No map can have all of the properties at once Equal areas Conformality Consistent Scale True-Compass Directions

Equal areas Places shown have the same proportions as they do on Earth. Example: Greenland 1/8 land area of S. America

Conformality Having correct shapes. Shows true shapes. Can show larger areas as closely as possible to their true shapes

Consistent Scale Uses the same scale for all parts of the map. Shows the true distances between places on Earth In most Cases maps showing large areas cannot be consistent-scale maps.

True-Compass Direction Parallels and meridians appear as straight lines. By following these lines you will be following the cardinal directions of N,S,E,&W. Straight line between two points on map determines exact directions and set course. (Navigators use these maps)

Map Projections Cylindrical Projections Conic Projections Flat Plane Projections Gnomonic Projection Robinson Projection Goode s Interrupted

Cylindrical Projections Straight lines of latitude and Longitude are Perpendicular Little distortion near the equator Best Known: Mercator conformal and true-compass direction map, but distortion near poles makes size of land and water areas inaccurate. Land shapes correct areas distorted valuable to navigator

Conic Projections Cannot map the entire world. Used for middle latitudes between 30 0 and 60 0 north latitudes, and between 30 0 and 60 0 south latitudes Best Known: Lambert Conformal Conical Important because it shows the true shapes of areas. Albers Equal Area Conical Consistent scale and is used when the size of land and water areas must be accurate. (military and engineering maps)

Flat Plane Projections Used to map areas of the North and South poles. Areas near that point show little distortion Farther away from the point the greater the distortion of area, shape, and scale. Shows no more that ½ of the Earth at one time. Also called Azimuthal Projection

Gnomonic Projection Circles of latitude lines and straight longitude lines form a wheel-like pattern. Especially useful to navigators because the shortest distance between two places on the map is found by drawing a straight line between them {this line is actually a part of a -great circle any imaginary line that circles Earth and divides it into 2 equal parts Navigators use these along with true-compass direction maps to make their travel plans.

Robinson Projection Equal areas shown with high degree of accuracy Conformal except near edges of map where distortion increases Valuable for showing entire world.

Goode s Interrupted High degree of accuracy in area and shape Distorted direction and scale. Valuable for showing Land masses.

Points to Remember The projection one chooses to use depends on the information one wants. All Maps are projections they transfer Earth s features from the globe to a flat surface (map). When large areas of Earth are mapped, distortion is more serious. When mapping small areas like cities, distortion is not usually evident.