ရာသီ season

A season is a division of the year,^[1] marked by changes in weather, ecology and hours of daylight. Seasons result from the yearly orbit of the Earth around the Sun and the tilt of the Earth's rotational axis relative to the plane of the orbit.^[2][3] In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to go into hibernation or to migrate, and plants to be dormant.

Red and green trees in spring

During May, June, and July, the northern hemisphere is exposed to more direct sunlight because the hemisphere faces the sun. The same is true of the southern hemisphere in November, December, and January. It is the tilt of the Earth that causes the Sun to be higher in the sky during the summer months which increases the solar flux. However, due to seasonal lag, June, July, and August are the hottest months in the northern hemisphere and December, January, and February are the hottest months in the southern hemisphere.
In temperate and subpolar regions, four calendar-based seasons (with their adjectives) are generally recognized: spring (vernal), summer (estival), autumn (autumnal) and winter (hibernal). In American English and Canadian English, fall is sometimes used as a synonym for both autumn and autumnal. Ecologists often use a six-season model for temperate climate regions that includes pre-spring (prevernal) and late summer (serotinal) as distinct seasons along with the traditional four.

A tree in winter

The six ecological seasons

The four calendar seasons, depicted in an ancient Roman mosaic from Tunisia.

An Empire style chariot clock depicting an allegory of the four seasons. France, c. 1822.

Hot regions have two or three seasons; the rainy (or wet, or monsoon) season and the dry season, and, in some tropical areas, a cool or mild season.
In some parts of the world, special "seasons" are loosely defined based on important events such as a hurricane season, tornado season, or a wildfire season.

ရာသီဆိုသည်မှာ နေ(တနင်္ဂနွေဂြိုဟ်)၏ သွားလမ်းအတိုင်း တစ်ပတ်ပြည့်အောင် လှည့်ပတ်သွားလာသော အချိန်ကာလကို အပိုင်းအစု ခွဲခြားသတ်မှတ်ထားသော အချိန်ပိုင်း ဖြစ်သည်။ နေသည် ရက်ပေါင်း ၃၆၅ ၁/၄ ရက်ကြာမှ ရာသီစက်ကို တစ်ပတ်ပတ်မိရာ၊ ထိုကာလကို ၁၂ ပိုင်းပိုင်း၍ တစ်ပိုင်းကို တစ်ရာသီဟု ခေါ်သည်။ တစ်ရာသီတွင် နက္ခတ်ခရီးအားဖြင့် ကိုးပါဒ်၊ သို့မဟုတ် (လေးပါဒ်သည် နက္ခတ်တလုံးနှင့် ညီမျှသဖြင့်) နှစ်လုံးတစ်ပါဒ် လှည့်ပတ်သည်။ နေတစ်ပတ် ပတ်ချိန်ကို တစ်နှစ်ဟု ခေါ်သည်။
နေတစ်ပတ် ပတ်ချိန်၏ ကာလအပိုင်းအခြားကို ၁၂ ပိုင်း ခွဲစိတ်မှတ်သားရာတွင် အကြမ်းအားဖြင့် လပြည့်ခြင်းသည် ၁၂ ကြိမ်ရှိ၍ လကွယ်ခြင်းသည် ၁၂ ကြိမ်ရှိသဖြင့် လဆန်းစမှ လကွယ်အထိ ကာလကို တစ်ပိုင်း၊ သို့မဟုတ် တစ်လအဖြစ် သတ်မှတ်ကြသည်။ ၂၆၅ ၁/၄ ရက်ကို ၁၂ ပိုင်း အညီအမျှ မပိုင်းချေ။ ထို့ကြောင့် လအားဖြင့် တစ်နှစ်လျှင် ရက်စုံ(ရက် ၃ဝ)ခြောက်လနှင့် ရက်မစုံ (၂၉)ရက် ခြောက်လဟူ၍ ရက်ပေါင်း ၃၅၄ ရက်သာ ရှိသဖြင့် နေသွားအတိုင်း တစ်နှစ်သည် လဆန်းသည်မှ ကွယ်သည်အထိ လဝန်း လှည့်ချိန် ၁၂ ကြိမ်ထက် ၁၁ ၁/၄ ရက် ပိုနေသည်။ ထိုပိုသောရက်များကို စုမှတ်၍ သုံးနှစ်လျှင် တစ်ကြိမ် ဝါကြီးထပ်၊ ဝါငယ်ထပ် စသည်ဖြင့် ဒုတိယဝါဆိုလဟူ၍ တစ်လတိုးဖြည့်ကာ ဖြည့်သွင်း ခုနှိမ်ရသည်။ ဝါကြီးထပ်လျှင် လေးလရက်စုံ သတ်၍ ကဆုန်၊ နယုန်ပထမဝါဆို၊ ဒုတိယဝါဆို လေးလလုံး ရက်ပေါင်း ၃ဝ စီ ထားသည်။ ဝါငယ်ထပ်လျှင်မူ နယုန်လအဖို့ ရက်မစုံ ၂၉ ရက် ထားမြဲ ဖြစ်သည်။ထိုနည်းဖြင့် နေလှည့်ချိန်တစ်နှစ်နှင့် လဆန်းအချိန်မှ ကွယ်ချိန် အထိ ၁၂ လကို တစ်ပြေးတည်း ညီမျှသွားစေသည်။
ဆယ့်နှစ်လ၊ သို့မဟုတ် ဆယ့်နှစ်ရာသီကို မြန်မာအမှတ်အသား အားဖြင့် တန်ခူး၊ ကဆုန်၊ နယုန်၊ ဝါဆို၊ ဝါခေါင်၊ တော် သလင်း၊ သီတင်းကျွတ်၊ တန်ဆောင်မုန်း၊ နတ်တော်၊ ပြာသို၊ တပို့တွဲနှင့် တပေါင်းဟူ၍ အစဉ်လိုက် အမည်မှည့်ခေါ်ထားသည်။
ဗေဒင်အလိုအားဖြင့်မူ လဆန်းမှလကွယ်ချိန်ကို တစ်ရာသီ မမှတ်ဘဲ၊ နက္ခတ် ၂၇ လုံး လှည့်ပုံအလိုက် နက္ခတ်လှည့်ချိန် နှစ်လုံးတစ်ပါဒ်ကာလကို တစ်ရာသီဟု မှတ်ယူသည်။ ထိုကြောင့် လဆန်းမှ လကွယ်အထိဖြစ်သော မြန်မာလနှင့် နက္ခတ်တစ်ခွင် တစ်ခွင်၌ မကူးပြောင်းမီ တည်ချိန်ဖြစ်သော ဗေဒင်အလို ရာသီသည် တစ်ထပ်တည်း မကျချေ။ ရက်အများဆုံး ထပ်ဆုံတတ်သည့် ရာသီအလိုက် မြန်မာလများကို ဗေဒင်ရာသီနှင့် ယှဉ်တွဲ၍ တန်ခူးကို မိဿ၊ ကဆုန်ကို ပြိဿ၊ နယုန်ကို မေထုန် စသည်ဖြင့် မှတ်သားကြရသည်။ မြန်မာလကို ဝေါဟာရလဟု ခေါ်၍ ဗေဒင်နက္ခတ်အလိုအားဖြင့် သတ်မှတ်သောလကို ရာသီလဟု ခေါ်သည်။
အနောက်နိုင်ငံသားတို့၏ အလိုအရ သဘာဝအလျှောက် အပူအအေးနှင့် နေ့တာညတာ ပြောင်းလဲခြင်းများကို လိုက်၍ တစ်နှစ်တည်းဟူသော အချိန်ကို နွေကူးရာသီ၊ နွေရာသီ၊ ဆောင်းကူးရာသီ၊ ဆောင်းရာသီဟူ၍ ရာသီဥတု လေးပိုင်းခွဲခြား ထားသည်။ မြောက်ကမ္ဘာလုံးခြမ်းတွင် မတ်လ၊ ဧပြီလနှင့် မေလတို့သည် နွေကူး ရာသီလများဖြစ်၍ ဇွန်၊ ဇူလိုင်နှင့် ဩဂုတ်လများသည် နွေလများ ဖြစ်ကြသည်။ ဆောင်းကူးရာသီလများတွင် စက်တင်ဘာ၊ အောက်တိုဘာနှင့် နိုဝင်ဘာလများ ပါဝင်၍ ဒီဇင်ဘာ၊ ဇန်နဝါရီနှင့် ဖေဖော်ဝါရီလများသည် ဆောင်းလများ ဖြစ်ကြလေသည်။ တောင်ကမ္ဘာလုံးခြမ်းရှိ ရာသီဥတုများမှာ မြောက်ကမ္ဘာလုံးခြမ်းရှိ ရာသီဥတုများနှင့် လုံးဝဆန့်ကျင်လေသည်။
ရာသီဥတုအပြောင်းအလဲဖြစ်ရသည်မှာ ကမ္ဘာကနေကို ပတ်၍သွားနေခြင်းကြောင့် ဖြစ်သည်။ ကမ္ဘာသည် နေကို တစ်နှစ်တွင် တစ်ပတ်ပတ်မိအောင် သွားလျက်ရှိ၍ ထိုသို့ သွားနေစဉ် မိမိ၏ သွားရာလမ်းကြောင်းကို ၂၃ ၁/၂ ဒီဂရီ စောင်း၍ သွားနေလေသည်။ ထို့ကြောင့် ကမ္ဘာ့ဝင်ရိုးသည် နေဘက်သို့ စောင်းနေချိန်တွင် မြောက်ကမ္ဘာလုံးခြမ်း၌ နေရောင်ကို ပိုမိုရရှိ၍ နေမှဝေးရာဘက်သို့ စောင်းနေချိန်တွင် ရရှိသော နေရောင်မှာ နည်းပါး သွားလေသည်။ မြောက်ကမ္ဘာလုံးခြမ်း၌ နေရောင် ပိုမိုရရှိနေချိန်တွင် နေ့တာရှည်၍ ညဉ့်တာတိုသည်။ နေရောင် အရနည်းသွားသောအခါ နေ့တာတို၍ ညဉ့်တာ ရှည်လာသည်။
ကမ္ဘာပေါ်ရှိ အရာများအနက် အပင်များသည် ရာသီ အလိုက် အပြောင်းလဲဆုံး ဖြစ်ကြသည်။ နွေကူးရာသီတွင် အပင်ရှိ အရွက်နှင့် အဖူးကလေးများ ထွက်လာကြသည်။ ဝတ်မှုန်များ စပ်ယှက်မှု အောင်မြင်ကြသည်။ အခေါက်၏ အောက်ဘက်၌ အရစ်သစ်များ စတင်ဖြစ်ပေါ်လေသည်။ နေ့တာရှည်သည့် နွေရာသီတွင် နေမှစွမ်းအင်ကို အများဆုံး ရရှိသဖြင့် အရွက်များသည် စတာ့(ကစီ)ကို အများဆုံးပြုလုပ်ကြသည်။ ဆောင်းကူးရာသီတွင် အသီးများ မှည့်ကြ၍ အရွက်များမှာ ဆောင်ရွက်ရန်လုပ်ငန်း ပြီးဆုံးသွားသကဲ့သို့ အရောင်များ ညှိုးပြီးလျှင် ကြွေကျကုန်လေသည်။ ဆောင်းရာသီသို့ ရောက်သောအခါ အပင်အမြောက်အမြား သေကုန်ကြ၍ ကျန်အပင်အချို့က အနားယူကြသည်။ အဖူးများတွင် အအေးဒဏ်ကို ခံနိုင်ရန် ဖယောင်းသားတက်လာ၍ အစေ့များ၌ အခွံမာများ ဖြစ်ပေါ်လာကြလေသည်။
တိရစ္ဆာန်တို့သည်လည်း များသောအားဖြင့် ရာသီအလိုက် အပြောင်းအလဲရှိကြလေသည်။ အအေးဒဏ်မှ လွတ်ကင်းစေရန် ငှက်များသည် နယ်ပြောင်းကြသည်။ဆောင်းရာသီတွင် သားမွေးရှိ တိရစ္ဆာန်များ၌ သစ်လွင်၍ ထူထဲသောအမွေးများ ပေါက်လာကြသည်။ အချို့တိရစ္ဆာန်များက တစ်ဆောင်းတွင်းလုံး အိပ်၍ နေကြသည်။ (ဆောင်းခိုကြသည်)။ နယ်ပြောင်းခြင်းနှင့် ဆောင်းခိုခြင်းမရှိသော တိရစ္ဆာန်များက အခြားနည်းများဖြင့် အအေးဒဏ်မှ အကာအကွယ်ရှာကြသည်။ နွေကူးရာသီ စတင်လာသောအခါတွင် ငှက်များ၊ ပိုးကောင်များ၊ တွားသွားတိရစ္ဆာန်များနှင့် နို့တိုက်သတ္တဝါများသည် သားငယ်ကို မွေးဖွားကြသဖြင့် တောများသည် ယင်းတို့၏အသံများဖြင့် ဆူညံလျက် ရှိတော့သည်။ ရှိရှိသမျှ တိရစ္ဆာန်များအဖို့ နွေရာသီသည် အလုပ်လုပ်ချိန်ဖြစ်၍ ဆောင်းကူးရာသီသည် အစာစားချိန် ဖြစ်လေသည်။
လူတို့သည်လည်း ရာသီဥတုအလိုက် ပြင်ဆင်မှုများကို ပြုလုပ်ကြလေသည်။ အဝတ်အမျိုးမျိုးကို ရာသီအလိုက် ချုပ်လုပ်ကြသည်။ အဝတ်အမျိုးမျိုးကို ရာသီအလိုက် ချုပ်လုပ်ကြသည်။ ကစားခုန်စားဘက်တွင် အမျိုးမျိုးပြောင်းလဲ၍ ကစားကြသည်။ တောင်သူလယ်သမားများကလည်း ရာသီအလိုက် ထွန်ယက်ခြင်း၊ စိုက်ပျိုးခြင်း၊ ရိတ်သိမ်းခြင်း စသည်တို့ကို ပြုလုပ်ကြလေသည်။^[၁]

nationalgeographic

Geography is the study of places and the relationships between people and their environments. Geographers explore both the physical properties of Earth’s surface and the human societies spread across it. They also examine how human culture interacts with the natural environment, and the way that locations and places can have an impact on people. Geography seeks to understand where things are found, why they are there, and how they develop and change over time.

Ancient Geographers

The term "geography" comes to us from the ancient Greeks, who needed a word to describe the writings and maps that were helping them make sense of the world in which they lived. In Greek, geo means “earth” and -graphy means “to write.”  Using geography, Greeks developed an understanding of where their homeland was located in relation to other places, what their own and other places were like, and how people and environments were distributed. These concerns have been central to geography ever since.

Of course, the Greeks were not the only people interested in geography. Throughout human history, most societies have sought to understand something about their place in the world, and the people and environments around them.

Indeed, mapmaking probably came even before writing in many places. But ancient Greek geographers were particularly influential. They developed very detailed maps of areas in and around Greece, including parts of Europe, Africa, and Asia. More importantly, they also raised questions about how and why different human and natural patterns came into being on Earth’s surface, and why variations existed from place to place. The effort to answer these questions about patterns and distribution led them to figure out that the world was round, to calculate Earth’s circumference, and to develop explanations of everything from the seasonal flooding of the Nile River to differences in population densities from place to place.

During the Middle Ages, geography ceased to be a major academic pursuit in Europe. Advances in geography were chiefly made by scientists of the Muslim world, based around the Arabian Peninsula and North Africa. Geographers of this Islamic Golden Age created the world’s first rectangular map based on a grid, a map system that is still familiar today. Islamic scholars also applied their study of people and places to agriculture, determining which crops and livestock were most suited to specific habitats or environments.

In addition to the advances in the Middle East, the Chinese empire in Asia also contributed immensely to geography. Until about 1500, China was the most prosperous civilization on Earth. The Chinese were scientifically advanced, especially in the field of astronomy. Around 1000, they also achieved one of the most important developments in the history of geography: They were the first to use the compass for navigational purposes. In the early 1400s, the explorer Cheng Ho embarked on seven voyages to the lands bordering the China Sea and the Indian Ocean, establishing China’s dominance throughout Southeast Asia.

Age of Discovery

Through the 13th-century travels of the Italian explorer Marco Polo, Europeans learned about the riches of China. Curiosity was awakened; a desire to trade with wealthy Asian cultures motivated a renewed interest in exploring the world. The period of time between the 15th and 17th centuries is known in the West as the Age of Exploration or the Age of Discovery.

With the dawn of the Age of Discovery, the study of geography regained popularity in Europe. The invention of the printing press in the mid-1400s helped spread geographic knowledge by making maps and charts widely available. Improvements in shipbuilding and navigation facilitated more exploring, greatly improving the accuracy of maps and geographic information.

Greater geographic understanding allowed European powers to extend their global influence. During the Age of Discovery, European nations established colonies around the world. Improved transportation, communication, and navigational technology allowed countries such as the United Kingdom to successfully govern colonies as far away as the Americas, Asia, Australia, and Africa.

Geography was not just a subject that made colonialism possible, however. It also helped people understand the planet on which they lived. Not surprisingly, geography became an important focus of study in schools and universities.

Geography also became an important part of other academic disciplines, such as chemistry, economics, and philosophy. In fact, every academic subject has some geographic connection. Chemists study where certain chemical elements, such as gold or silver, can be found. Economists examine which nations trade with other nations, and what resources are exchanged. Philosophers analyze the responsibility people have to take care of the Earth.

Emergence of Modern Geography

Some people have trouble understanding the complete scope of the discipline of geography because, unlike most other disciplines, geography is not defined by one particular topic. Instead, geography is concerned with many different topics—people, culture, politics, settlements, plants, landforms, and much more.

What distinguishes geography is that it approaches the study of diverse topics in a particular way (that is, from a particular perspective). Geography asks spatial questions—how and why things are distributed or arranged in particular ways on Earth’s surface. It looks at these different distributions and arrangements at many different scales. It also asks questions about how the interaction of different human and natural activities on Earth’s surface shape the characteristics of the world in which we live.

Geography seeks to understand where things are found and why they are present in those places; how things that are located in the same or distant places influence one another over time; and why places and the people who live in them develop and change in particular ways. Raising these questions is at the heart of the “geographic perspective.”

Exploration has long been an important part of geography. But exploration no longer simply means going to places that have not been visited before. It means documenting and trying to explain the variations that exist across the surface of Earth, as well as figuring out what those variations mean for the future.

The age-old practice of mapping still plays an important role in this type of exploration, but exploration can also be done by using images from satellites or gathering information from interviews. Discoveries can come by using computers to map and analyze the relationship among things in geographic space, or from piecing together the multiple forces, near and far, that shape the way individual places develop.

Applying a geographic perspective demonstrates geography’s concern not just with where things are, but with “the why of where”—a short, but useful definition of geography’s central focus.

The insights that have come from geographic research show the importance of asking “the why of where” questions. Geographic studies comparing physical characteristics of continents on either side of the Atlantic Ocean, for instance, gave rise to the idea that Earth’s surface is comprised of large, slowly moving plates—plate tectonics.

Studies of the geographic distribution of human settlements have shown how economic forces and modes of transport influence the location of towns and cities. For example, geographic analysis has pointed to the role of the U.S. Interstate Highway System and the rapid growth of car ownership in creating a boom in U.S. suburban growth after World War II. The geographic perspective helped show where Americans were moving, why they were moving there, and how their new living places affected their lives, their relationships with others, and their interactions with the environment.

Geographic analyses of the spread of diseases have pointed to the conditions that allow particular diseases to develop and spread. Dr. John Snow’s cholera map stands out as a classic example. When cholera broke out in London, England, in 1854, Snow represented the deaths per household on a street map. Using the map, he was able to trace the source of the outbreak to a water pump on the corner of Broad Street and Cambridge Street. The geographic perspective helped identify the source of the problem (the water from a specific pump) and allowed people to avoid the disease (avoiding water from that pump).

Investigations of the geographic impact of human activities have advanced understanding of the role of humans in transforming the surface of Earth, exposing the spatial extent of threats such as water pollution by manmade waste. For example, geographic study has shown that a large mass of tiny pieces of plastic currently floating in the Pacific Ocean is approximately the size of Texas. Satellite images and other geographic technology identified the so-called “Great Pacific Garbage Patch.”

These examples of different uses of the geographic perspective help explain why geographic study and research is important as we confront many 21st century challenges, including environmental pollution, poverty, hunger, and ethnic or political conflict.

Because the study of geography is so broad, the discipline is typically divided into specialties. At the broadest level, geography is divided into physical geography, human geography, geographic techniques, and regional geography.

Physical Geography

The natural environment is the primary concern of physical geographers, although many physical geographers also look at how humans have altered natural systems. Physical geographers study Earth’s seasons, climate, atmosphere, soil, streams, landforms, and oceans. Some disciplines within physical geography include geomorphology, glaciology, pedology, hydrology, climatology, biogeography, and oceanography.

Geomorphology is the study of landforms and the processes that shape them. Geomorphologists investigate the nature and impact of wind, ice, rivers, erosion, earthquakes, volcanoes, living things, and other forces that shape and change the surface of the Earth.

Glaciologists focus on the Earth’s ice fields and their impact on the planet’s climate. Glaciologists document the properties and distribution of glaciers and icebergs. Data collected by glaciologists has demonstrated the retreat of Arctic and Antarctic ice in the past century.

Pedologists study soil and how it is created, changed, and classified. Soil studies are used by a variety of professions, from farmers analyzing field fertility to engineers investigating the suitability of different areas for building heavy structures.

Hydrology is the study of Earth’s water: its properties, distribution, and effects. Hydrologists are especially concerned with the movement of water as it cycles from the ocean to the atmosphere, then back to Earth’s surface. Hydrologists study the water cycle through rainfall into streams, lakes, the soil, and underground aquifers. Hydrologists provide insights that are critical to building or removing dams, designing irrigation systems, monitoring water quality, tracking drought conditions, and predicting flood risk.

Climatologists study Earth’s climate system and its impact on Earth’s surface. For example, climatologists make predictions about El Nino, a cyclical weather phenomenon of warm surface temperatures in the Pacific Ocean. They analyze the dramatic worldwide climate changes caused by El Nino, such as flooding in Peru, drought in Australia, and, in the United States, the oddities of heavy Texas rains or an unseasonably warm Minnesota winter.

Biogeographers study the impact of the environment on the distribution of plants and animals. For example, a biogeographer might document all the places in the world inhabited by a certain spider species, and what those places have in common.     

Oceanography, a related discipline of physical geography, focuses on the creatures and environments of the world’s oceans. Observation of ocean tides and currents constituted some of the first oceanographic investigations. For example, 18th-century mariners figured out the geography of the Gulf Stream, a massive current flowing like a river through the Atlantic Ocean. The discovery and tracking of the Gulf Stream helped communications and travel between Europe and the Americas.

Today, oceanographers conduct research on the impacts of water pollution, track tsunamis, design offshore oil rigs, investigate underwater eruptions of lava, and study all types of marine organisms from toxic algae to friendly dolphins.

Human Geography

Human geography is concerned with the distribution and networks of people and cultures on Earth’s surface. A human geographer might investigate the local, regional, and global impact of rising economic powers China and India, which represent 37 percent of the world’s people. They also might look at how consumers in China and India adjust to new technology and markets, and how markets respond to such a huge consumer base.

Human geographers also study how people use and alter their environments. When, for example, people allow their animals to overgraze a region, the soil erodes and grassland is transformed into desert. The impact of overgrazing on the landscape as well as agricultural production is an area of study for human geographers.

Finally, human geographers study how political, social, and economic systems are organized across geographical space. These include governments, religious organizations, and trade partnerships. The boundaries of these groups constantly change.

The main divisions within human geography reflect a concern with different types of human activities or ways of living. Some examples of human geography include urban geography, economic geography, cultural geography, political geography, social geography, and population geography. Human geographers who study geographic patterns and processes in past times are part of the subdiscipline of historical geography. Those who study how people understand maps and geographic space belong to a subdiscipline known as behavioral geography.

Many human geographers interested in the relationship between humans and the environment work in the subdisciplines of cultural geography and political geography.
Cultural geographers study how the natural environment influences the development of human culture, such as how the climate affects the agricultural practices of a region. Political geographers study the impact of political circumstances on interactions between people and their environment, as well as environmental conflicts, such as disputes over water rights.

Some human geographers focus on the connection between human health and geography. For example, health geographers create maps that track the location and spread of specific diseases. They analyze the geographic disparities of health-care access. They are very interested in the impact of the environment on human health, especially the effects of environmental hazards such as radiation, lead poisoning, or water pollution.

Geographic Techniques

Specialists in geographic techniques study the ways in which geographic processes can be analyzed and represented using different methods and technologies. Mapmaking, or cartography, is perhaps the most basic of these. Cartography has been instrumental to geography throughout the ages.

As early as 1500 BCE, Polynesian navigators in the Pacific Ocean used complex maps made of tiny sticks and shells that represented islands and ocean currents they would encounter on their voyages. Today, satellites placed into orbit by the U.S. Department of Defense communicate with receivers on the ground called global positioning system (GPS) units to instantly identify exact locations on Earth.

Today, almost the entire surface of Earth has been mapped with remarkable accuracy, and much of this information is available instantly on the internet. One of the most remarkable of these websites is Google Earth, which “lets you fly anywhere on Earth to view satellite imagery, maps, terrain, 3D buildings, from galaxies in outer space to the canyons of the ocean.” In essence, anyone can be a virtual Christopher Columbus from the comfort of home.

Technological developments during the past 100 years have given rise to a number of other specialties for scientists studying geographic techniques. The airplane made it possible to photograph land from above. Now, there are many satellites and other above-Earth vehicles that help geographers figure out what the surface of the planet looks like and how it is changing.

Geographers looking at what above-Earth cameras and sensors reveal are specialists in remote sensing. Pictures taken from space can be used to make maps, monitor ice melt, assess flood damage, track oil spills, predict weather, or perform endless other functions. For example, by comparing satellite photos taken from 1955 to 2007, scientists from the U.S. Geological Survey (USGS) discovered that the rate of coastal erosion along Alaska’s Beaufort Sea had doubled. Every year from 2002 to 2007, about 45 feet per year of coast, mostly icy permafrost, vanished into the sea.

Computerized systems that allow for precise calculations of how things are distributed and relate to one another have made the study of geographic information systems (GIS) an increasingly important specialty within geography. Geographic information systems are powerful databases that collect all types of information (maps, reports, statistics, satellite images, surveys, demographic data, and more) and link each piece of data to a geographic reference point, such as geographic coordinates. This data, called geospatial information, can be stored, analyzed, modeled, and manipulated in ways not possible before GIS computer technology existed.

The popularity and importance of GIS has given rise to a new science known as geographic information science (GISci). Geographic information scientists study patterns in nature as well as human development. They might study natural hazards, such as a fire that struck Los Angeles, California, in 2008. A map posted on the internet showed the real-time spread of the fire, along with information to help people make decisions about how to evacuate quickly. GIS can also illustrate human struggles from a geographic perspective, such as the interactive online map published by the New York Times in May 2009 that showed building foreclosure rates in various regions around the New York City area.

The enormous possibilities for producing computerized maps and diagrams that can help us understand environmental and social problems have made geographic visualization an increasingly important specialty within geography. This geospatial information is in high demand by just about every institution, from government agencies monitoring water quality to entrepreneurs deciding where to locate new businesses.

Regional Geography

Regional geographers take a somewhat different approach to specialization, directing their attention to the general geographic characteristics of a region. A regional geographer might specialize in African studies, observing and documenting the people, nations, rivers, mountains, deserts, weather, trade, and other attributes of the continent. There are different ways you can define a region. You can look at climate zones, cultural regions, or political regions. Often regional geographers have a physical or human geography specialty as well as a regional specialty.

Regional geographers may also study smaller regions, such as urban areas. A regional geographer may be interested in the way a city like Shanghai, China, is growing. They would study transportation, migration, housing, and language use, as well as the human impact on elements of the natural environment, such as the Huangpu River.

Whether geography is thought of as a discipline or as a basic feature of our world, developing an understanding of the subject is important. Some grasp of geography is essential as people seek to make sense of the world and understand their place in it. Thinking geographically helps people to be aware of the connections among and between places and to see how important events are shaped by where they take place.  Finally, knowing something about geography enriches people’s lives—promoting curiosity about other people and places and an appreciation of the patterns, environments, and peoples that make up the endlessly fascinating, varied planet on which we live.

Geography

From Wikipedia, the free encyclopedia

"Geographical" redirects here. For other uses, see Geography (disambiguation).

Physical map of the Earth

Geography (from Greek γεωγραφία, geographia, literally "earth description"^[1]) is a field of science devoted to the study of the lands, the features, the inhabitants, and the phenomena of Earth.^[2] The first person to use the word "γεωγραφία" was Eratosthenes (276–194 BC).^[3] Four historical traditions in geographical research are spatial analysis of the natural and the human phenomena (geography as the study of distribution), area studies (places and regions), study of the human-land relationship, and research in the Earth sciences.^[4] Nonetheless, modern geography is an all-encompassing discipline that foremost seeks to understand the Earth and all of its human and natural complexities—not merely where objects are, but how they have changed and come to be. Geography has been called "the world discipline" and "the bridge between the human and the physical science". Geography is divided into two main branches: human geography and physical geography.^[5][6][7]

Contents

• 1 Introduction
• 2 Branches
  • 2.1 Physical geography
  • 2.2 Human geography
  • 2.3 Integrated geography
  • 2.4 Geomatics
  • 2.5 Regional geography
  • 2.6 Related fields
• 3 Techniques
  • 3.1 Cartography
  • 3.2 Geographic information systems
  • 3.3 Remote sensing
  • 3.4 Quantitative methods
  • 3.5 Qualitative methods
• 4 History
• 5 Notable geographers
• 6 Institutions and societies
• 7 Publications
• 8 See also
• 9 Notes and references
• 10 External links

Multimedia

Multimedia is content that uses a combination of different content forms such as text, audio, images, animation, video and interactive content. Multimedia contrasts with media that use only rudimentary computer displays such as text-only or traditional forms of printed or hand-produced material.
Multimedia can be recorded and played, displayed, dynamic, interacted with or accessed by information content processing devices, such as computerized and electronic devices, but can also be part of a live performance. Multimedia devices are electronic media devices used to store and experience multimedia content. Multimedia is distinguished from mixed media in fine art; by including audio, for example, it has a broader scope. The term "rich media" is synonymous for interactive multimedia. Hypermedia scales up the amount of media content in multimedia application.

Contents

• 1 Categorization of multimedia
• 2 Major characteristics of multimedia
• 3 Terminology
  • 3.1 History of the term
  • 3.2 Word usage and context
• 4 Usage / Application
  • 4.1 Creative industries
    • 4.1.1 Commercial uses
    • 4.1.2 Entertainment and fine arts
    • 4.1.3 Education
    • 4.1.4 Journalism
    • 4.1.5 Engineering
    • 4.1.6 Industry
    • 4.1.7 Mathematical and scientific research
    • 4.1.8 Medicine
    • 4.1.9 Document imaging
    • 4.1.10 Disabilities
  • 4.2 Miscellaneous
• 5 Structuring information in a multimedia form
• 6 Conferences
• 7 See also
• 8 References
• 9 External links