Obj 1.5: Use and Interpret Maps September 14, 2017 Obj 1.5: Use and Interpret Maps

What is a map? Maps are used to represent and identify spatial patterns and processes at different scales. A small scale map shows the largest area

Types of Maps Reference Maps: shows the location of the geographic areas for which census data are tabulated and disseminated. The maps display the boundaries, names and unique identifiers of standard geographic areas, as well as major cultural and physical features, such as roads, railroads, coastlines, rivers and lakes. Can be a political map (shows governmental boundaries of countries, states, and counties, the location of major cities, and they usually include significant bodies of water.) or a physical map (shows the same data found on a political map, but their primary purpose is to show landforms like deserts, mountains and plains.) Thematic Maps: designed for a specific purpose Choropleth Map Dot Density Map Graduated Symbol Map Isoline Map Cartogram

Thematic Maps

Choropleth Map •Applies distinctive colors to represent different quantities or densities •Typically on a map of a formal region (political)

Dot Density Map Shows distribution using a concentration of dots Each dot represents the same quantity Used for population density

Graduated Symbol Map •Portrays numerical quantities •Symbols are drawn proportional to the value at that location

Isoline Map •Used to portray quantities that vary smoothly over a given area •Joins locations with the same value •Used for climate variables

Cartogram Deliberately distort map shapes to achieve special effects

Map Projections

Map Projections Because the earth is a sphere and maps are flat, all maps distort some aspect of reality The process of showing a curved surface on a flat surface is done using a map projection Cartographers, or map makers, decide whether they want to preserve area, shape, distance, or direction on their map accurately, knowing that other elements will have to be less accurate as the earth is “flattened” on their map Why are we changing maps?

Map Projection chart Complete the Map Projection Chart using your text, review book, and the Internet. Put your completed activity in your Unit Portfolio. You may work with a partner on this activity. The projections are Conic, Robinson, Peters, and Mercator. Purpose Strengths Distortion Projection Navigation Directions are shown accurately Land masses near the poles appear large Spatial Distributions Related to Area Sizes of land masses are accurate Shapes are inaccurate, especially near poles General Use in Midlatitude Countries Size and shape are both close to reality Longitude lines converge at only one pole General Use No major distortion Area, shape, size, and direction are all distorted