Modern tools of geography

Rapid developments in technology have made several new tools available. These tools already have provided a wide range of valuable information about the earth’s surface. Remote sensing, the gathering and recording of information through aerial photographs and satellite images, ranks among the most important of the new methods.

Aerial photographs. Geographers use aerial photographs – pictures taken from above the earth- to study the relationships involving people and places that are not easily seen from ground level. Aerial photographs of traffic patterns, for example, can be used to help plan new highways. Military planners can see troop movements and rocket launch sites. Foresters can spot diseased or insect-infested trees in rugged terrain that would be hard to reach on foot. Aerial photographs even can show features of the ocean floor.

Because aerial photographs provide such accurate and detailed information, cartographers rely on them as a source of information when making maps. Most aerial photographs used to make maps are taken by cameras in high altitude airplanes and are developed in strips of overlapping pictures. An instrument called a stereoscope converts a pair of overlapping aerial photographs into a three-dimensional view of the area.

Elevations appear somewhat distorted on aerial photographs because the cameras taking the pictures is closer to the tops of the mountains than to the valleys. As a result, mountains appear larger that the more distant valleys. This distortion is corrected by using a viewing instrument called a stereoplotter, which gives a more accurate three-dimensional view of the earth.

Satellite images. Many of the satellites circling (revolving around) the earth have special sensors called multispectral scanners. These scanners record observations electronically and send them to the ground stations. Computers then translate the data into electronic images, making false-color pictures. Even though the pictures are taken from far in space, they are so detailed that they can show houses or even sailboats on a lake.

An extraordinary group of earth satellites known as Landsats take many of the satellite images. These satellites circle the earth 14 times every 24 hours, silently scanning, collecting and sending back a greater view of the world than any eye could ever see.

In addition to globes, maps and remotely sensed images geographers use tables, charts, graphs and diagrams to help them in their work. Geographers also use computers to solve geographic problems as well as to make maps and graphics.

Answer the following questions.

1. Why are aerial photographs and satellite images especially useful to geographers?

2. Why do elevations appear somewhat distorted on aerial photographs?

3. How do computers help geographers?

4. How do geographers use new advances in technology to acquire data?

5. How do people in the armed forces, and people in business use the products of professional cartographers?

Дата добавления: 2015-11-16