Representing Earth’s Surface Chapter 1 Section 3

Determining Location Latitude and longitude are lines on the globe that are used to determine location. Latitude is distance north or south of the equator, measured in degrees. The middle latitude, at 0 degrees, is the equator Longitude is distance east or west of the prime meridian, measured in degrees. The middle longitude, at 0 degrees, is the prime meridian

Royal Observatory in Greenwich, London

Globes Advantages: Accurate shapes and sized of continents Disadvantages: Too small to show details

Projection Maps: Mercator Projection Advantages Rectangular Longitude lines are parallel Directions shown accurately Disadvantages Sizes and distances distorted

Projection Maps: Robinson Projection Advantages Most distances, sizes, and shapes are accurate Disadvantages Distortion around edges of maps Discuss: How do shapes in the continents differ between the Mercator and the Robinson maps?

Projection Maps: Conic Projection Advantages: Great accuracy over small areas Used for road and weather maps Disadvantages: Lots of distortion on most of the map

Projection Maps: Gnomonic Projection Advantages: Reliably shows the shortest distance between two points Disadvantages Exact distances and directions distorted

Topographic Maps Topographic maps represent Earth’s surface in three dimensions; they show elevation, distance directions, and slope angles. Contour lines are lines on a topographic map that indicate an elevation. (hachure marks) Contour interval is the distance in elevation between adjacent contour lines.

Topographic Maps Discuss: Where is the land flattest? Where is the land steepest? How do the contour lines show a stream?

Geologic Maps A map that shows the type and age of exposed rock

GPS

GPS Satellites and computers allow scientists to more precisely analyze Earth’s physical properties. Can detect latitude, longitude, altitude/elevation, speed, and direction Three satellite signals are detected by a receiver. The distance from the satellites to the receiver is calculated, and the location is determined using the triangulation method. A fourth signal is then used to mathematically determine exact position.

Review Describe the two sets of lines that are used on globes and some maps What happens to images from a globe when they are transferred to a flat surface? What is the purpose of contour lines on a topographic map?