Maps & Globes

Remember: Earth is tipped on its axis of rotation (relative to our plane of orbit around the sun).

A map is a way of representing an objects (or objects) real-world location on an artificially created two-dimensional surface. Maps have been used by humans since about 1400 B.C. when they appear in the archaeological record of the ancient Egyptians.Later, as their cultures mixed, these early attempts were improved upon by the Greeks. In 150 A.D. Ptolemy (an Egyptian) added the first lines of latitude and longitude used on a map. Today typical references used for mapping include latitude, longitude, the location of the north and south poles, and the location of the equator.Latitude and Longitude are cartographic lines superimposed on the surface of the earth. These lines create a grid coordinate system that is used to pinpoint locations on earth - each point on the globe is assigned an unique pair of longitude and latitude values so that it may be identified easily and accurately. Latitude lines (or parallels) run from east to west horizontally around the globe. Longitude lines (or meridians) run vertically from the North and South Poles.Like other circles, latitude and longitude are measured in units of degrees, minutes, and seconds with a total of 360 degrees possible (1 degree = 60 minutes and 1 minute - 60 seconds). A protractor can be used to measure these distances.Longitude values range from 180 degrees west to 180 degrees east, and are measured from the Prime Meridian, or zero degrees longitude (the longitude line passing through Greenwich, England). The longitude line directly opposite to the Prime Meridian is called the International Dateline and can be considered as either 180 east or west). The Equator is the line of latitude that divides the globe into two equal halves, the Northern and Southern Hemispheres. The Equator is designated as 0 latitude. Latitude is measured North or South of the Equator with a range of 0 to 90 degrees. Latitude lines below the equator have negative values, while those above the equator have positive values. The full range of latitude values then is -90 (S) to +90 (N) degrees. Some familiar examples:1. The Tropic of Capricorn (23.5 degrees S)2. The Antarctic Circle (66.5 degrees S)3. Tropic of Cancer (23.5 degrees N)4. The Arctic Circle (66.5 degrees N).Look at how the curvature of the earth affects the shape of the latitude and longitude lines. All of the longitude lines are identical so degrees of longitude are constant, always covering the same distance (about 60 nautical miles). In contrast, degrees of latitude vary. Near the equator, a degree of latitude is approximately 60 nautical miles, but as you approach the poles that distance goes to zero.It is important to keep in mind that the earth is curved and maps are flat, so they do not quite represent reality. To properly map the earth, a planet shaped globe is required. Cartographers represent the curvature of the earth on a flat surface by means of a projection. Regions are projected on to a map in different ways in order to correct for real direction, area or shape. The most common projection used is the Mercator, which was invented in 1568 by the German Gerhard Kramer (a.k.a. Gerardus Mercator). The Mercator distorts the size of the continents however because it makes the earth the same width at the at the equator and the poles.The Data Behind a MapReference Datum:A reference datum is a known and constant surface which can be used to describe the location of unknown points. On Earth, the normal reference datum is sea level. On other planets, such as the Moon or Mars, the datum is the average radius of the planet.Map Projections:A map projection is a way of representing the 3-dimensional surface of the Earth on a flat piece of paper.Distortion:Each of the different types of projections have strengths and weaknesses, and knowledge of the advantages and disadvantages of a particular map projection will often help you to choose what map you want to use for a particular project.Grid systems:A grid system allows the location of a point on a map (or on the surface of the earth) to be described in a way that is meaningful and universally understood.Coordinate systems:There are several types of grids (a.k.a. coordinate systems) used to divide the earths surface. Four of these are in common use on maps published in the United States: geographic, universal transverse mercator (UTM), state plane, and public land survey coordinate systems.Much of the information discussed above is applicable to all types of maps.

Types of MapsThere are several types of maps. Each show different information. Most maps include a compass rose, which indicates which way is north, south, east and west. They also include a scale so you can estimate distances. Here's a look at some different types of maps. Climate mapsgive general information about the climate and precipitation (rain and snow) of a region. Cartographers, or mapmakers, use colors to show different climate or precipitation zones. Economic or resource mapsfeature the type of natural resources or economic activity that dominates an area. Cartographers use symbols to show the locations of natural resources or economic activities. For example, oranges on a map of Florida tell you that oranges are grown there. Physical mapsillustrate the physical features of an area, such as the mountains, rivers and lakes. The water is usually shown in blue. Colors are used to show reliefdifferences in land elevations. Green is typically used at lower elevations, and orange or brown indicate higher elevations. Political mapsdo not show physical features. Instead, they indicate state and national boundaries and capital and major cities. A capital city is usually marked with a star within a circle. Road mapsshow majorsome minor highwaysand roads, airports, railroad tracks, cities and other points of interest in an area. People use road maps to plan trips and for driving directions. Topographic mapsinclude contour lines to show the shape and elevation of an area. Lines that are close together indicate steep terrain, and lines that are far apart indicate flat terrain.

Article 1The term Global Warming refers to the rise in the temperature of planet earth which will bring an end to the mountains old human civilization. The Green house gages including CFC-11 and CFC- 12 make the earth hotter and hotter by absorbing maximum quantity of thermal radiation of the sun. These gasses permit the rays of the sun to penetrate but dont let the thermal radiations escape from the earths atmosphere once they enter it. This causing what is termed as the Greenhouse effect which is responsible for the increase in the temperature all over the world. The rise in temperature disturbs the rain cycle, the ecological balance, the cycle of seasons etc. It adversely affects vegetation and agriculture. Thus, we have to face frequent floods and droughts through the world. With the increase in temperature and the melting of glaciers, even snowfall has reduced its occurrence and intensity. The winter temperatures are showing a gradual increase. With the warming of the planet there is also rise in humidity because the rise in temperature has increase the rate of evaporation. The local governments should work against the emission of the Greenhouse gages by improving the vehicles, creating awareness among the people, selling environment-friendly appliances; encourage recycling of paper, metal and glass etc. Such efforts are needed by the people at the grass-root level. Only then we can combat this problem in an effective way.

NATURAL DISASTERAnatural disasteris a majoradverse eventresulting fromnatural processesof the Earth; examples includefloods,volcanic eruptions,earthquakes,tsunamis, and other geologic processes. A natural disaster can cause loss of life or property damage,[1]and typically leaves some economic damage in its wake, the severity of which depends on the affected population'sresilience, or ability to recover.[2]An adverse event will not rise to the level of a disaster if it occurs in an area without vulnerable population.[3][4]In a vulnerable area, however, such asSan FranciscoandNepal, an earthquake can have disastrous consequences and leave lasting damage, requiring years to repair. In 2012, there were 905 natural disasters worldwide, 93% of which were weather-related disasters. Overall costs were US$170 billion and insured losses $70 billion. 2012 was a moderate year. 45% were meteorological (storms), 36% were hydrological (floods), 12% were climatological (heat waves, cold waves, droughts, wildfires) and 7% were geophysical events (earthquakes and volcanic eruptions). Between 1980 and 2011 geophysical events accounted for 14% of all natural catastrophes.