© 2014 Pearson Education, Inc. Chapter 2 Lecture McKnight's Physical Geography 11e Lectures Chapter 2 Portraying Earth © 2014 Pearson Education, Inc. Andrew Mercer Mississippi State University

© 2014 Pearson Education, Inc. Learning Goals of this Chapter Explain why no map of the world can be as accurate as a globe. Define map scale. Define graphic scale of a map. Identify examples of graphic scales from a map. Define fractional scale of a map. Identify examples of fractional scales from a map. Define verbal scale of a map. Identify examples of verbal scales from a map. Describe equivalent map projection.

© 2014 Pearson Education, Inc. Learning Goals of this Chapter Describe conformal map projection. Describe compromise map projection. Explain when an equivalent map projection is most suited for use in geographic studies. Explain when a conformal map is most suited for use in geographic studies. Explain when a compromise map is most suited for use in geographic studies. Describe cylindrical projection. Describe some of the best uses for maps with a cylindrical projection.

© 2014 Pearson Education, Inc. Learning Goals of this Chapter Describe planar projection. Describe some of the best uses for maps with a planar projection. Describe conic projection. Describe some of the best uses for maps with a conic projection. Describe pseudocylindrical projection. Describe some of the best uses for maps with a pseudocylindrical projection. Explain how isolines are used to convey information on a map.

© 2014 Pearson Education, Inc. Learning Goals of this Chapter Describe how a GPS unit determines its location. Describe some common uses of GPS. Define remote sensing. Discuss the kinds of information that can be gathered by remote sensing. Explain how GIS helps in the analysis of geographic data.

© 2014 Pearson Education, Inc. Portraying Earth Maps and Globes Map Scale Map Projections and Properties Families of Map Projections Conveying Information on Maps GPS – the Global Positioning System Remote Sensing Geographic Information Systems

© 2014 Pearson Education, Inc. Maps and Globes Best ways to portray Earth Advantages of Globes –Maintains correct geographic relationships between points –Can accurately represent spatial relationships between points on Earth Disadvantages of Globes –Only can see a hemisphere at a time –Large and bulky –Cannot contain much detail

© 2014 Pearson Education, Inc. Maps and Globes Flat representation of the Earth’s surface Show 4 key properties of a region –Size –Shape –Distance –Direction Maps are imperfect, since the Earth is a sphere

© 2014 Pearson Education, Inc. Map Scale Maps are always smaller than the area they represent Need map scales to help understand areal distances on maps Scale is relationship between area on map and area on Earth Three primary types –Graphic –Fractional –Verbal

© 2014 Pearson Education, Inc. Map Scale Large versus small map scales

© 2014 Pearson Education, Inc. Map Projections Challenge of the cartographer (“mapmaker”) –Combine geographic exactness of globe with convenience of flat map Definition of map projection Principle behind map projections Three primary types –Equivalent – ratio of areal size on map and Earth is the same –Conformal – shape of locations on the map is the same as on Earth –Compromise - projections that are neither conformal nor equivalent, but are almost both (e.g. Robinson projection)

© 2014 Pearson Education, Inc. Map Projections Equivalence versus conformality dilemma

© 2014 Pearson Education, Inc. Families of Map Projections Cylindrical Projections –“Wrap” the globe in a cylinder of paper –Paper tangent to Earth at Equator –Conformal projection –Mercator projection is most famous –Definition of a loxodrome

© 2014 Pearson Education, Inc. Families of Map Projections Plane Projections –Project globe onto a paper that is tangent to globe at some point –Displays one hemisphere well –Equivalent projection –An example is an orthographic plane projection (Fig in the textbook)

© 2014 Pearson Education, Inc. Families of Map Projections Conic Projections –Project the map onto a cone tangent to or intersecting the globe –Standard parallel –Good for mapping small areas on Earth –Impractical for global mapping

© 2014 Pearson Education, Inc. Families of Map Projections Pseudocylindrical Projections –A mix of conformal and equivalent –Central parallel and meridian cross at right angles –Oval shaped; distortion increases as you move away from the center

© 2014 Pearson Education, Inc. Families of Map Projections Interrupted Projections –Minimize distortion –Discontinuous map, shapes and sizes maintained –Typically oceans are distorted, land masses maintain original shape and size –Goode’s projection

© 2014 Pearson Education, Inc. Conveying Information on Maps Need several properties of maps to help with interpretation: –Title –Date –Legend –Scale –Direction –Location –Data Source –Map Projection

© 2014 Pearson Education, Inc. Conveying Information on Maps Definition of an isoline Many types –Elevation contour line – line of equal elevation –Isobar – line of constant pressure –Isotherm – line of constant temperature –Isohyet – line of constant rain –Isogonic line – line of equal magnetic declination Drawing isolines

© 2014 Pearson Education, Inc. Conveying Information on Maps Example contour line construction (Fig. 2-16)

© 2014 Pearson Education, Inc. Conveying Information on Maps Characteristics if isolines –Always closed lines (have no ends) –Can never touch or cross –Numerical difference between two lines is the interval –Isolines close together suggest a steep gradient, far apart a gentle gradient (Fig. 2-14)

© 2014 Pearson Education, Inc. Conveying Information on Maps Portraying three- dimensional landscape –Elevation contours –Digital Elevation Models

© 2014 Pearson Education, Inc. GPS – Global Positioning System GPS system –Based on global network of at least 24 high altitude satellites –4-6 in view at any time anywhere on Earth Wide Area Augmentation System (WAAS) –ground based correction to GPS

© 2014 Pearson Education, Inc. GPS – Global Positioning System Continuously Operating GPS Reference Stations (CORS) –Reference points used to correct for changing Earth surface GPS modernization Applications of GPS –Transportation –Emergency Management

© 2014 Pearson Education, Inc. Remote Sensing Measurement by a device not in contact with Earth’s surface Common types include: –Aerial Photographs –Orthophoto maps –Visible Light and Infrared (IR) Scanning –Thermal IR scanning –Radar and Sonar Aerial photographs – not frequently used anymore due to satellites

© 2014 Pearson Education, Inc. Remote Sensing Orthophoto maps –Photographic maps that are multi-colored and distortion free –Useful in low-lying coastal regions to show marsh topography

© 2014 Pearson Education, Inc. Remote Sensing Visible light and IR scanning –Based off of visible light and IR part of electromagnetic spectrum (Fig. 2-21) –Shows “false color”

© 2014 Pearson Education, Inc. Remote Sensing Thermal IR scanning –Scans in the thermal IR part of spectrum –Shows images based on temperature –Often utilized in meteorology

© 2014 Pearson Education, Inc. Remote Sensing Multispectral remote sensing –Detect multiple bands in the EM spectrum –Landsat (Fig. 2-24) –Earth Observing System Satellites –Commercial High- Resolution satellites –Radar and sonar

© 2014 Pearson Education, Inc. GIS – Geographic Information Systems Computer systems used to analyze and display spatial data Layers of data used in mapping (overlay analysis) Requires high powered computing to process multiple maps

© 2014 Pearson Education, Inc. Tools of the Geographer Vast array of maps, remotely sensed satellite imagery, and computer applications Difficult to determine the best way to use all of this information Need to choose effective maps and imagery Some tools better at identifying features on the Earth than others Ultimate goal: “To better understand Earth.”

© 2014 Pearson Education, Inc. Summary Maps are essential to portray features on the Earth’s surface Globes have several advantages and disadvantages Representing the Earth in 2-dimensions can be done through map projections Many different map projections exist Dilemma of equivalent versus conformal Need a map scale to identify how a map relates to the actual surface features on Earth

© 2014 Pearson Education, Inc. Summary Many other map properties are essential to interpreting a map Plotting isolines on a map can help with interpretation of features on the map The global positioning system (GPS) helps to identify location on the Earth’s surface Remote sensing is a measurement of the Earth’s surface from a system not on the Earth’s surface

© 2014 Pearson Education, Inc. Summary Many different remote sensing instruments exist, including satellite, radar, and sonar GIS are computer systems used to analyze and display spatial data, often in layers The geographer has many tools, but the ultimate goal is “To better understand Earth.”