Science notes Chapter 6
Section 1
- Topography is the shape of the land. An area’s topography may be flat, sloping, hilly, or mountainous.
- The topography of an area includes the area’s elevation, relief, and landforms.
- The height above sea level of a point on Earth’s surface is its elevation.
- The difference in elevation between the highest and lowest parts of an area is its relief.
- A landform is a feature of topography, such as a hill or valley, formed by the processes that shape Earth’s surface.
- There are tree main types of landforms: plains, mountains and plateaus.
- A plain is a landform made up of nearly flat or gently rolling land with low relief.
- A plain that lies along a seacoast is called a coastal plain.
- A plain that lies away from the coast is called an interior plain.
- A mountain is a landform with high elevation and high relief. Mountains usually occur as part of a mountain range.
- A mountain range is a group of mountains that are closely related in shape, structure, and age.
- A landform that has high elevation and more or less level surface is called a plateau.
- A large area of land where the topography is made up mainly of one type of landform is called a landform region.
Section 2
- A map is a flat model of all or part of Earth’s surface as seen above.
- A globe is a sphere that represents Earth’s surface.
- Maps and globes are drawn to scale and use symbols to represent topography and other features on Earth’s surface.
- A map’s scale relates distance on a map to a distance on Earth’s surface.
- Mapmakers use shapes and pictures called symbols to stand for features on earth’s surfaces.
- A map’s key, or legend, is a list of all the symbols used on the map with an explanation of their meaning.
- Two of the lines that make up the grid, the equator and prime meridian, are the baselines for measuring distances on Earth’s surface.
- A degree is 1/360 of the distance around a circle.
- The equator forms an imaginary line that circles Earth. The equator divides Earth into the Northern and Southern hemispheres.
- A hemisphere is one half of the sphere that makes up Earth’s surfaces.
- Another imaginary line, called the prime meridian, makes a half circle from the North Pole to the South Pole.
- The lines of latitude and longitude form a grid that can be used to find locations anywhere on Earth.
- The equator is the starting line for measuring latitude.
- The distance in degrees east or west of the prime meridian is called longitude.
- A map projection is a framework of lines that helps in transferring points on Earth’s three-dimensional surface onto a flat map.
- Three common map projections are the Mercator projection, the equal-area projection, and the conic projection.
- On a Mercator projection, all the lines of latitude and longitude appear as straight, parallel lines that form a rectangle. The North and South pole can’t be shown
- Equal-Area projection correctly shows the relative sizes of Earth’s landmasses. But the shapes of landmasses near the edges of the map appear stretched and curved.
- In a conic projection, lines of longitude appear as straight lines while lines of latitude are curved. There is little distortion on the maps that use this projection to show limited parts of Earth’s surface.
Section 3
- In surveying, mapmakers determine distances and elevations using instruments and the principles of geometry.
- With computers, map makers can store, process, and display map data electronically.
- The process by which mapmakers convert the location of map points to numbers is called digitizing.
- Computers produce maps using data from many sources, including satellites and the Global Positioning System.
- Pictures of the surface based on these data satellites collect are called satellite images.
- The Global Positioning System is a method of finding latitude, longitude and elevation of points on Earth’s surface using a network of satellites.
Section 4
- A topographic map is a map showing the surface features of an area.
- Map makers use contour lines to represent elevation, relief, and slope on topographic maps.
- A contour line connects points of equal elevation.
- The change in elevation from contour line to contour line is called the contour interval. (always the same in one map)
- Index contours are labeled with the elevation in round units, such as 1600 or 2000 feet above sea level.
- To read a topographic map, you must familiarize yourself with the map’s scale and symbols and interpret the map’s contour lines.
- Topographic maps have many uses in science and engineering, business, government, and everyday life.