What are satellites photographing?

Satellites capture images of the Earth's weather patterns, the growth of cities, the health of plants, and even individual buildings and roads. Satellites circle the Earth, or remain geostationary (in the same place with respect to the Earth), and send data back to the Earth via radio signals.

How have satellites changed map making?

Satellite images, which are accurate photographs of the Earth's surface, allow cartographers to precisely determine the location of roads, cities, rivers, and other features on the Earth. These images help cartographers create maps that are more accurate than ever before. Since the Earth is a dynamic and ever-changing place, satellite images are great tools that allow cartographers to stay up-to-date.

Satellites orbiting the Earth take photographs that make it possible to create extremely accurate maps.

Satellites orbiting the Earth take photographs that make it possible to create extremely accurate maps.

How much junk is there in space?

In addition to operational satellites, there are approximately 8,800 pieces of space junk surrounding the Earth, from tiny screws to booster rockets. There are plans for the future to build a radar system that would track every piece of space junk so that space vehicles and satellites can avoid irreparable damage.

How has GIS revolutionized cartography?

Geographic Information Systems (GIS) began in the 1960s with the popularity of computers. Though very simplistic in its beginning, new technology and inventions have expanded and enhanced the functions of GIS. GIS has revolutionized cartography by using computers to store, analyze, and retrieve geographic data, thus allowing infinite numbers of comparisons to be made quickly. The program formulates information into various "layers," such as the location of utility lines, sewers, property boundaries, and streets. These layers can be placed together in a multitude of combinations to create a plethora of maps, unique and suitable to each individual query. The versatility of GIS makes it indispensable to local governments and public agencies.

How can GIS help my town?

Your community can use GIS on a day-to-day basis and in emergency situations. GIS allows public works departments, planning offices, and parks departments to monitor

How did a map stop cholera?

In the 1850s an outbreak of cholera threatened London. Dr. John Snow, a British physician, mapped the deaths associated with the disease and determined that many deaths were occurring near one water pump. The pump handle was removed and the spread of the disease stopped. Prior to this time, the method by which cholera spread was unknown. Today, medical geographers and epidemiologists frequently use cartography to determine the cause and spread of disease or epidemics.

the status of the community's utilities, roads, and properties. In an emergency, GIS can give emergency teams the information they need to evacuate endangered areas and respond to the crisis.

How does a GPS unit know where I am?

Individual Global Positioning System (GPS) units on the Earth receive information from a U.S. military-run system of 24 satellites that circle the Earth and provide precise time and location data. The individual GPS unit receives data from three or more satellites that triangulate its absolute location on the Earth's surface. If you are carrying such a device, your absolute location is the same as that of the device.

How can GPS keep me from getting lost?

A GPS unit provides precise latitude and longitude for the location of the device. By using a hand-held GPS unit along with a map that provides latitude and longitude (such as a topographic map), you can determine your precise location on the Earth's surface. This is a valuable tool for those who hike or travel in remote regions and for ships at sea. GPS is now widely available in cars; as stand-alone, portable, pocket-sized devices; on cell phones; and even on the boxes that ship products that you buy. In short, GPS is used in all aspects of our lives.

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