physical geography 10th edition "chapter 2: portraying the earth" presentation

Chapter 2: Portraying Earth

Ashley AdamsDonald AgabaAlysha BaldwinCory Bragg

The Nature of Maps

MapA two-dimensional representation of Earth

and the spatial distribution of selected phenomena

Basic Abilities of Maps:

•Distance

•Size

•Shape in Their Horizontal Spatial Relationships

Maps are not perfectly Accurate!

It is impossible to portray the curved surface of the Earth on a flat piece of

paper

Map Essentials

MapA form of symbolization, governed by a set of conventions, that aim to communicate a

sense of place (second definition)

6 Groups of Maps:

1) Climate Maps

Give general information about climate and precipitation

2) Economic/Resource Map

Show the types of resources or

economic activities in an

area

3) Physical Maps

Illustrate the

physical features of

an area

4) Political Maps

Show state and national boundaries, & indicate capitals and major cities

5) Road Maps

6) Topographic Maps

Use contour lines to show shape and elevation of an area

Basic Elements of Maps

1. Title2. Date3. Legend4. Scale5. Direction6. Location7. Data Source8. Projection

The Roles of Globes

GlobeA Three-Dimensional Scale model of Earth

or other spheroid celestial body

Globes…

•Accurately represent spatial relationship of features on Earth’s surface

•Give a more realistic depiction of Earth than flat maps

Globe Disadvantages:

•Globes are cumbersome, and do not display much detail

•Globes are only visible to half of the human eye at a time

Map Projections: The Major DilemmaEquivalency vs. Conformity

•Which to EMPHASIZE?

SHAPEor

SIZE

•Which to SACRIFICE?

orSIZE

SHAPE

Equivalent Area Projection

Conformal Map Projection

The Robinson Projection

The 7 Projection Families:

Cylindrical Projection

Mercator Projection

Plane Projection

Conic Projection

Pseudocylindrical Projection

Interrupted Projection

Isolines

A device for portraying the spatial distribution of some phenomenon. It refers to any line that joins points of equal value of something

Also referred to as

•Isarithm•Isogram•Isopleth•Isometric Line

Elevation Contour LinesA line on a map joining points of equal

elevation

Q: What do Isolines signify?

A: Subtle features including…

1)Quantities of Precipitation (Isohyet):

2)Temperature (Isotherm):

3) Atmospheric Pressure (Isobar):

Isolines…

•Are ALWAYS closed lines (they have no end)

•Never touch or cross each other (w/ exceptions)

•Have Intervals (diff. between each line)

Patterns that are too large/abstract/detailed are often significantly clarified by the use of isolines

•Isolines close together – Rapid change

•Isolines far apart – Gradual change

Edmund Halley (1656 – 1742)

•English astronomer & Cartographer

•Produced the first published map with isolines in 1700

▫Showed isogonic lines in the Atlantic Ocean

1st Magnetic Declination Chart (1702)-Edmund Halley

Global Positioning System (GPS)

GPSA global navigation satellite system for

determining accurate positions on or near Earth’s surface

Developed in the 1970’s / 80’s by the U.S. Department of Defense

The system is based on a constellation of at least 24 high altitude satellites

4-6 satellites will be in view of any position on Earth

Wide Area Augmentation System (WAAS)

Was originally put to practice to increase the accuracy of the instrument based

flight approaches for airplanes

Continuously Operating GPS Reference Stations (CORS)

•Capable of detecting location differences of less than 1 centimeter of latitude, longitude, and elevation

•One way they are used is for the monitoring of slight changes in the ground surfaces

Geographic Information System

Geographic Information SystemComputer systems designed to analyze and

display spatial data

Overlay Analysis

The Role of The Geographer

Q: What is The Main Role of a Geographer?

A: To better understand Earth