Unit 1: Maps & Projections

Function of a Map Two purposes As reference tools To find locations, to find one’s way As communications tools To show the distribution of human and physical features

Scale Small scale – shows a large area without a lot of detail Ratio/fraction – shows the ratio of distance on a map compared to the real earth measurement. Bar/graphic – shows the ratio of the distance on the map to the distance on the earth Written – describes relation between map and Earth in words Small scale – shows a large area without a lot of detail Large scale – shows a small area with a lot of detail.

Scale

Questions 1. In what way do you most often use a map? Reference or communication? 2. Which map would have the largest scale?

Globe 3d representation of the earth Advantage: provides a way to view the earth as it travels through space Disadvantage: Can only see half of it at one time

Maps 2d representations of selected parts of the earth’s surface Advantage: easily portable and can be drawn to any scale needed Disadvantage: distortion occurs when as the earth’s surface is flattened to create a map

Types of Maps General reference or topographic map -natural and man-made features on the earth Thematic – emphasize specific kind of information Navigational – help users plot a course through water or air.

Political Shows features on the earth’s surface that humans have created. Cities, states, provinces, territories, and countries Physical See types of landforms and bodies of water in a specific area.

Thematic Climate, vegetation, natural resources, population density and economic activities Qualitative - use colors, symbols, dots or lines to see patterns Cartograms – info about a country based on data other than land area. Flow-line – illustrate movement of people, goods, ideas, and animals,

Questions 3. Which are you more likely to use, a physical map or a political map? Explain your answer. 4. Give one example of when a thematic is helpful and one example when it is not.

Map projections A way of drawing the earth’s surface that reduces distortion caused by presenting a round earth on flat paper. A cartographer will reduce some types of distortion by using different types of map projections Distance, shape, direction, or area/size may be distorted.

Planar Projection Projection on a flat surface. Also called Azimuthal which shows the earth so a line that from the central point on the map gives the shortest distance between two points. Size and shape are distorted.

Conical Projection Projected onto a cone Shows shape fairly accurate and used to show landmasses that cover large areas going east and west Distorts landmasses at the edges

Cylindrical Projections Projection onto a cylinder and shows the entire earth on one map. Three types Mercator Homolosine Robinson

Questions 5. Why are map projections needed? 6. What 4 things are distorted in a map projection?

Mercator Shapes of continents are distorted at the poles and somewhat compressed near the equator

Homolosine Oceans are divided Shows accurate shapes and sizes of the landmasses but distances on the map are not correct.

Robinson Shows entire earth almost true to sizes and shapes of continents and oceans. Shapes of the landforms near the poles appear flat.

U.S. Land Ordinance of 1785 Township and range system Township = 6 sq. miles on each side North–south lines = principal meridians East–west lines = base lines Range Sections

Township and Range System

Contemporary Tools Geographic Information Science (GIScience) Global Positioning Systems (GPS) Remote sensing Geographic information systems (GIS)

Questions 7. Which cylindrical map projection shows the world most accurately? 8. Discuss with your neighbor the last time you used GPS?