Maps, Projections, Tools

1. Unit 1- Introducing Basic Concepts Maps, Projections, Tools

2. Maps • Geography’s most important tool for thinking spatially about the distribution of features across Earth is a map • Definition: • A two-dimensional or flat-scale model of Earth’s surface • Science of mapmaking called cartography • A map serves two purposes: • Reference tool • Communications tool

3. History of the Map • Earliest Maps were reference tools • Designed to show a traveler how to get from Point A to Point B • Important Names • Eratosthenes • Coined the word “geography” • Determined circumference of the world • Ptolemy • Produced maps used for over 1000 years • Aristotle • Determined Earth was spherical • Exploration Age • Cartography revived during Age of Exploration thanks to Columbus, Magellan, and other explorers • Between 1470-1520 1st map with “America” labeled appears

4. Contemporary Mapping • Uses • Describe data • Sources of data • Tools for analysis • Example: • Hurricane Katrina • Representations of the world • Usually two-dimensional graphic representations that use lines and symbols to convey information or ideas about spatial relationships

5. Types of Maps • Topographic Maps • Designed to represent Earth’s surface and to show permanent features such as buildings, highways, field boundaries, and political boundaries • Device for representing the form of Earth’s surface is the contour • A line that connects points of equal distance above or below a zero data point, usually sea level

6. Types of Maps • Reference Maps • Show common features such as boundaries, roads, and mountains • Thematic Maps • Designed to represent the spatial dimensions of particular conditions, processes, or events • Types of Thematic Maps • Isopleth maps • Maps based on isolines • A line that connects places of equal data value • Dot maps • Single dot or other symbol represents a specified number of occurrences of some particular phenomenon or event • Choropleth map • Tonal shadings are graduated to reflect variations in numbers, frequencies, or densities

7. CHOROPLETH MAP

8. Map Scale: • refers to the relationship of a feature’s size on a map to its actual size on earth • Ratio between linear distance on a map and linear distance on Earth’s surface • Usually expressed in terms of corresponding lengths: • as in one centimeter equals one kilometer • Or as a representative fraction • Small scale maps= bigger fraction • Large scale maps = smaller fraction

9. Scale Differences: Maps of Florida The effects of scale in maps of Florida. (Scales from 1:10 million to 1:10,000)

10. Types of Scale • Fractional • shows the numerical ratio between distances on the map on earth’s surface • example: 1:24,000 • Means 1 map unit= 24, 000 units on ground Written • relationship between the map and earth distances in words • example: 1 inch equals 1 mile • 1st number represents map’s distance • 2nd number represents earth’s distance • Graphic • consists of a bar line marked to show distance on the earth’s surface • example: • What scale you use depends on what information you are portraying

11. talking map Projection • Definition: • the scientific method of transferring locations on the earth’s surface to a flat map • earth’s surface is curved and not a perfect sphere. It is impossible to represent on a flat plane without distortion • Four problems: • the shape of an area can be distorted • the distance between two points may increase or decrease • the relative size of different areas may be altered so that one area may appear larger • the direction from one place to another can be distorted.

12. the Solution????? • Different types of projections • Equidistant Projections • can represent distance accurately in only one direction (usually north-south) • usually provide accurate scale in perpendicular direction • most aesthetically pleasing • Conformal Projections • Projection on which compass directions are rendered accurately

13. Types of Map Projections: • Equal-Area: • Relative sizes of the landmasses on the map are the same as in reality • Minimizes distortion • Mercator: • Shape is distorted little • Direction is consistent • Map is rectangular • Distorts area • higher latitudes distorted - Greenland appears huge! • Fuller: • maintains accurate size and shape • completely rearranges direction • Robinson: • Useful for displaying oceans • Disadvantage = land areas are much smaller • distorts all 4 but minimizes errors in each (most balanced) • Azimuthal: • puts N or S pole at center of map • view of looking up or down at earth

15. Mercator Projection The world’s 24 standard time zones are often depicted using the Mercator projection.

16. Different Projections • Peters • Deliberate attempt to give prominence to underdeveloped countries of equatorial regions and the Southern Hemisphere • Adopted by United Nations • Shape gives “shock value” • Cartogram • Space is transformed according to statistical factors • Largest mapping units represent greatest statistical values

17. Geographic Grid • Definition: • System of imaginary arcs drawn in a grid pattern on Earth’s surface • The location of any place on Earth’s surface can be described precisely by meridians and parallels • Meridian • An arc drawn between the North and South poles • Location of each meridian = longitude • Measured from the Prime Meridian (0-180 degrees East or West) • Greenwich, England • Parallel • A circle drawn around the globe parallel to the equator and at right angles to the meridians • Location of each parallel= Latitude • Measured from the Equator (0-90 degrees North or South)

18. Basic Tools and Methods of Human Geographers • Observation • Information must be collected and data recorded • Methods: • Fieldwork • Use of scientific instruments • Laboratory experiments • Archival searches • Remote sensing • Aerial photography or satellite imagery designed to record data on visible, infrared, and microwave sensor systems • Visualization or Representation Written descriptions • Charts • Diagrams • Tables • Analysis • Heart of geographic research • Objective analysis is to discover patterns and establish relationships so that hypotheses can be established and models be built

20. Remote Sensing • Remote Sensing • acquisition of data about earth’s surface from satellite images that are transmitted in digital form. • Remote-Sensing satellites scan the Earth’s surface • Geographers use remote sensing to map the changing distribution of a wide variety of features such as: • Agriculture, drought, and sprawl • Example • used with Hurricane Katrina to monitor areas of impact

21. Global Positioning System (GPS) • Definition: • System that accurately determines the precise location of something on Earth • GPS in the United States includes three elements: • Satellites placed in predetermined orbits by the U.S. military • 24 in operation, 3 in reserve • Tracking stations to monitor and control the satellites • A reciever that can locate at least 4 satellites to pinpoint locations • GPS devices enable private individuals to contribute to the production of accurate digital maps • Travelers can upload information about streets, buildings, etc. to improve maps in the future • GPS is most commonly used for navigation • Can also be used for fieldwork for history, geography, etc.

22. Geographic Information System (GIS) • Definition: • a computer system that can capture, story, query, analyze, and display geographic data. • Produces maps that are more accurate and attractive than hand-drawn maps • The position of any object on Earth can be measured and stored in a computer • A map can be created by retrieving a number of stored objects and combining them to form an image • Each type of information is stored in a layer • Layers can be compared t0 show relationships among different kinds of information

23. Layers of a GIS • Each layer represents a different category of information.

24. Geographical Information Systems • GIS technology can render visible many aspects of geography there were previously unseen • Images that could never be drawn by hand • GIS can put places under the microscope, creating detailed new insights using huge databases • Military applications • Allows infantry commanders to calculate line of sight from tans and defensive emplacements • Allows cruise missiles to fly below enemy radar • GIS allows an enormous range of problems to be addressed • Geodemographic research • Uses census and commercial data about the populations of small districts in creating profiles for market research