Maps • An attempt to portray things that are distributed across space.
Map Creation • Simplification – narrow down the criteria used in order to produce a clear and uncluttered view of whatever it is the cartographer wants the map to show. • Classification - how a cartographer categorizes the data he or she wants to show on a map. (example: precipitation) • Symbolization - a cartographer takes data and renders it into symbols such as shapes, colors and patterns to portray it on the map. • Induction – estimation – it’s not always possible to have data for everyplace on the map.
Reading a Map • Scale - the size of an area - relationship between the distances on the map and the actual distances on Earth • IMPORTANT – it can influence how things appear. • Map Scale portrayed in three ways. • Representative Fraction – ie: 1:100,000,000 • Written Statement / Verbal – one inch to 1,600 miles • Graphic Scale / Bar Scale - represents a segment of a ruler
Scale – Large or Small??? • Depends on how much detail is needed. • Large-scale Maps • Larger fraction • more detail • Smaller area • Small-scale Maps – smaller number, less detail . • Smaller fractions • Less detail • Larger area
How To Read a Map • Map Key – explains lines, symbols and colors on a map. • Dots: major cities or capitals • Compass Rose – cardinal directions
Latitude • Latitude – run west to east BUT measure north and south • parallel • Varying lengths • longest: the equator, • shortest: the poles • Thermal characteristics • Low latitudes – 0-30o – warm all year, no distinct seasonality • Mid latitudes – 30 – 600 – distinct winter and summer • High latitudes – 60 – 90o – cold almost all year, short “warm” season
Longitude • Longitude – run north and south – measure east to west • 00 – Prime Meridian – Greenwich, England • 1800 – international date line
Hemispheres • The Equator and and the Prime Meridian divide the earth into spheres. • The Equator - Northern and Southern Hemisphere • The Prime Meridian – Eastern and Western Hemisphere.
Map Projection • A 3D surface to a flat surface. • Distortion will occur in at least one area: • Area • Direction • Distance • Shape • no "best" projection.
Types of Map Projections • The Globe • Mercator (Transverse, Oblique and Space Oblique) • Cylindrical • Robinson • Conic (Albers Equal, Lambert Conformal, Equidistant (Simple Conic), Polyconic, Bipolar Oblique Conic Conformal • Sinusoidal Equal Area • Orthographic • Stereographic • Gnomonic • Azimuthal Equidistant • Lambert Azimuthal Equal Area
Types Map Projections • The Globe • True: Directions, Distances, Shapes and Areas • Great circles—The shortest distance between any two points on the surface of the Earth can be found quickly and easily along a great circle. • Disadvantages: • Even the largest globe has a very small scale and shows relatively little detail. • Costly to reproduce and update. • Difficult to carry around and bulky to store.
Types Map Projections • Mercator
Types of Map Projections • Robinson
Types of Map Projections • Conic (Simple)
How Maps are Made • Today satellites are used to make maps. • Geographic Information Systems (GIS) • Maps are produced faster and are easily changed.
General Purpose Maps • Maps that show a wide range of general information about an area. • Political – names and boundaries of cities and other human-made features of a place. • Physical - labels landforms and water features • Contour – shows elevation
Special Purpose Maps • Or Thematic Maps, which present specific kinds of information – themes or patterns. • Climate • Natural resources • Population density • Historic