Models of Earth

Globes are 3-Dimensional Models of the Earth

Types of Maps 1. Political Shows political (national and state) boundaries (like a globe)

Types of Maps 1. Political 2. Road Shows interstate system, highways, and smaller roads, depending on the map Used for navigation (getting from “here” to “there”

Types of Maps 1. Political 2. Road 3. Weather Shows pressure systems, cloud cover, rainfall, weather forecasts

Types of Maps 1. Political 2. Road 3. Weather 4. Bathymetric The ocean floor, ocean features Topography of the ocean

Types of Maps 1. Political 2. Road 3. Weather 4. Bathymetric 5. Topographic Shows the differences in elevation (relief) of an area Shows man-made features of the land as well as its natural features

A. Paper Maps are Flat 2-Dimensional Representations of Earth’s Surface Problems: Not as accurate as a 3-D Globe model Earth’s features become distorted (they don’t look right)

B. Map Making Surveyors Use distance and elevation information from known points to create maps Known points of elevation are called: bench marks, metal stakes placed in stone and marked with the location and elevation Aerial (from the sky) photography also helps make maps

Benchmarks Mauna Kea, Hawaii

Modern surveyors use: Compass Infrared theodolite & GPS

C. Map Projections Cartographers (map makers) illustrate world maps as a projection to reduce distortion Map projection – transferring a curved surface (the Earth, sphere) to a flat one (the map). Common map projections: Mercator, Gnomonic (polar), and (Poly)conic

I. Mercator Projection Map The mercator map projection shows the view of Earth as if a large cylinder of paper had been wrapped around the globe. This is the most common type of projection

Mercator Projection Map -Disadvantage  Major distortion effects near the poles (land looks larger than what it really is) +Advantage  Indicates true directions as straight lines of latitude and longitude, makes a rectangular grid pattern

II. Gnomonic or polar Projection Map A gnomonic or polar projected map is created as if a piece of paper had been placed on a point on the Earth.

III. (Poly)Conic Projection Map The (poly)conic map projection shows the view of Earth as if a large paper cone had been wrapped around the globe. This type of map is useful for mapping areas in the middle latitudes.

Identify the type of map projection. Write the name of the type of projection in your notes

Review: What type of halves is the Earth divided into? North-South Hemispheres are separated by the imaginary line called the Equator East-West Hemispheres are separated by imaginary lines called the Prime Meridian (Greenwich Meridian) and the International Date Line

Latitude and Longitude Grid of imaginary lines placed over Earth Every location on the Earth has a specific latitude and longitude “address.”

Latitude Latitude lines circle the Earth horizontally, parallel to the Equator (0 Degrees) Latitude is measured in Degrees North or South of the equator (0-90 Degrees) HHS is at 37° North Latitude

Longitude Longitude lines are half-circles that extend vertically between the poles Longitude is measured in Degrees East or West of the Prime Meridian (0-180 Degrees) HHS is at 78° West Longitude

D. How do you know the size of landforms or the distance between cities on a map? The map scale indicates how the map’s features and distances compare with the actual Earth The comparison is given as a ratio: 1:24,000

Map Scale as a Ratio 1 : 24,000 means that 1 map unit equals = 24,000 units on Earth

E. How do you determine direction on a map? Usually, most modern maps place North at the top Compass Rose indicates direction Geographic North vs Magnetic North Are they the same? No, because… the Earth is tilted on its axis

Earth Observing System The satellites in the Earth Observing Systems (EOS) will contain sensors to monitor global climate change.

Landsat Satellite Images

Global Positioning System GPS is a system of satellites and receivers that allow accurate positioning on the Earth. 24 satellites work together GPS Ground Receiver GPS Satellite

Mapmaking & Technology Computer image modeled from global topography provided by NOAA