求The ERDAS Field Guide第一章内容
Chapter 2 Vector Layers
本章教学要求：有关专业英语单词
Introduction
ERDAS IMAGINE is designed to integrate two data types, raster and vector, into one system. The vector data structure in ERDAS IMAGINE is based on the ArcInfo data model (developed by ESRI, Inc. ). This chapter describes vector data, attribute information, and symbolization.
You can use ArcInfo coverages directly without importing them.
记住 Figure 2-1: Vector Elements 中的英文词。
ArcGIS Integration
ArcGIS Integration is the method you use to access the data in a geodatabase. ERDAS IMAGINE has always supported ESRI data formats such as coverages and shapefiles, and now, using ArcGIS Vector Integration, ERDAS IMAGINE can also access CAD and VPF data on the internet.
Chapter 3
Raster and Vector Data Sources
本章教学要求：1、重点：Satellite data部分
2其余部分，仅要求标题有关专业英语单词
Introduction
This chapter is an introduction to the most common raster and vector data types that can be used with the ERDAS IMAGINE software package.
The raster data types covered include: （See text，
Importing and Exporting（不用理会)
Satellite Data
There are several data acquisition options available including photography, aerial sensors, and sophisticated satellite scanners. However, a satellite system offers these advantages:
• Easily processed and analyzed by a computer.
• Many satellites orbit the Earth, so the same area can be covered on a regular basis for change detection.
• Once the satellite is launched, the cost for data acquisition is less than that for aircraft data.
• Satellites have very stable geometry, meaning that there is less chance for distortion or skew in the final image.
Satellite System
A satellite system is composed of a scanner with sensors and a satellite platform. The sensors are made up of detectors.
（See the detailed in text）
Satellite Characteristics
The U. S. Landsat and the French SPOT satellites are two important data acquisition satellites. They have several characteristics in common:
• Both scanners can produce nadir views.
• They have sun-synchronous orbits, meaning that they rotate around the Earth at the same rate as the Earth rotates on its axis, so data are always collected at the same local time of day over the same region.
• They both record electromagnetic radiation in one or more bands. Multiband data are referred to as multispectral imagery. Single band, or monochrome, imagery is called panchromatic.
Figure 3-1 Multispectral Imagery Comparison
IKONOS（was launched in September of 1999）
The resolution of the panchromatic sensor is 1 m. The resolution of the multispectral scanner is 4 m. The swath width is 13 km at nadir.
Table 3-4: IKONOS Bands and Wavelengths
补：美DigitalGlobel (EarthWatch)公司的QuickBird（快鸟）图像，波段分布与IKONOS同，但pan和multispectral分辨率分别达0.6和2.4米，为民用卫星之最。
IRS (Indian Remote Sensing Satellite)
Landsat 1-5 (See the histoty in text)
Landsats 1, 2, and 3 are no longer operating, but Landsats 4 and 5 are still in orbit gathering data.
Landsats 1, 2, and 3 gathered Multispectral Scanner (MSS) data and Landsats 4 and 5 collect MSS and TM data.
MSS (Multispectral Scanner)
MSS data are widely used for general geologic studies as well as vegetation inventories.
Table 3-8: MSS Bands and Wavelengths
TM （Thematic Mapper）
The TM scanner is a multispectral scanning system much like the MSS. TM has higher spatial, spectral, and radiometric resolution than MSS.
The spatial resolution of TM is 28.5 × 28.5 m for all bands except the thermal (band 6), which has a spatial resolution of 120 × 120 m.
Table 3-9: TM Bands and Wavelengths
Landsat 7
launched in 1999, uses Enhanced Thematic Mapper Plus (ETM+) to observe the Earth.
Table 3-10: Landsat 7 Characteristics
NLAPS
NOAA Polar Orbiter Data
AVHRR
See Table 3-11: AVHRR Bands and Wavelengths, also Figure 3-1.
OrbView-3 (US) 类似 IKONOS.
SeaWiFS（Sea-viewing Wide Field-of-View Sensor）
SPOT
The sensors operate in two modes, multispectral（20m） and panchromatic (10m).
Also see Figure 3-1.
Panchromatic
XS (see table 3-14: SPOT XS Bands and Wavelengths)
SPOT 4 (was launched in 1998)
增加一个1.58 to 1.75 μm的近红外波段；See table 3-15.
补：SPOT 5—— Panchromatic 波段达2.5米分辨率。
补：我国资源一号卫星CBERS
Radar Data
Researchers are finding that a combination of the characteristics of radar data and visible/infrared data is providing a more complete picture of the Earth. In the last decade, the importance and applications of radar have grown rapidly.
Advantages of Using Radar Data
• Radar microwaves can penetrate the atmosphere day or night under virtually all weather conditions. 全天候
• Under certain circumstances, radar can partially penetrate arid and hyperarid surfaces, revealing subsurface features of the Earth.
• For research on bodies of water.
Radar Sensors
Radar images are generated by two different types of sensors:
SLAR (Figure 3-4)
SAR — uses a side-looking, fixed antenna to create a synthetic aperture.
Active and Passive Sensors
An active radar sensor gives off a burst of coherent radiation that reflects from the target, unlike a passive microwave sensor which simply receives the low-level radiation naturally emitted by targets.
Applications for Radar Data
• Geology
• Classification
• Glaciology
• Oceanography
• Hydrology
• Ship monitoring
• Offshore oil activities
• Pollution monitoring
Image Data from Aircraft
This is useful if there is not time to wait for the next satellite to pass over a particular area, or if it is necessary to achieve a specific spatial or spectral resolution that cannot be attained with satellite sensors.
GPS Data
Chapter 4 Image Display
本章教学要求：1、重点：RGB Displaying Raster Layers 部分
2 、Using the Viewer 部分，结合实习1
Introduction
This section defines some important terms that are relevant to image display. This may differ from other systems, such as Microsoft Windows NT.
The display hardware contains the memory that is used to produce the image. This hardware determines which types of displays are available (e.g., true color or pseudo color) and the pixel depth (e.g., 8-bit or 24-bit).
Display Memory Size
• display resolution—the number of pixels that can be viewed on the display screen.
• the number of bits for each pixel or pixel depth.
Pixel（file pixel display pixel）
• the data file value(s) for one data unit in an image
• one grid location on a display or printout
To display an image, a file pixel that consists of one or more numbers must be transformed into a display pixel with properties that can be seen, such as brightness and color.
Colors（RGB）
Red, green, and blue can be added together to produce a wide variety of colors, are therefore the additive primary colors.
（三原色和三补色，及其它颜色特性，推荐阅读彭书 58-66页）
color guns
On a display, color guns direct electron beams that fall on red, green, and blue phosphors. The phosphors glow at certain frequencies to produce different colors.
The combination of the three color guns, each with 28 possible brightness values, yields 224 or 16,777,216 possible colors for each pixel on a 24-bit display. (line 7-9, page 110)
Colormap and Colorcells
A colormap is an ordered set of colorcells, which is used to perform a function on a set of input values. To display or print an image, the colormap translates data file values in memory into brightness values for each color gun.
（SEE Table 4-1）
Colorcells
There is a colorcell in the colormap for each data file value. he red, green, and blue values assigned to the colorcell control the brightness of the color guns for the displayed pixel.
Colormap vs. Lookup Table
The colormap is a function of the display hardware, whereas a lookup table is a function of ERDAS IMAGINE.
Display Types
• 8-bit PseudoColor
• 24-bit DirectColor
• 24-bit TrueColor
32-bit Displays
A 32-bit display is a combination of an 8-bit PseudoColor and 24-bit DirectColor, or TrueColor display.
8-bit PseudoColor： a colormap with 256 colorcells.
This display grants a small number of colors to ERDAS IMAGINE. It works well with thematic raster layers containing less than 200 colors and with gray scale continuous raster layers. For image files with three continuous raster layers (bands), the colors are severely limited.
24-bit DirectColor or 24-bit TrueColor
两种方式（Colorcell or color gun）达到24位彩色实时显示的目的：
enables you to view up to three continuous raster layers (bands) of data at one time, creating displayed pixels that represent the relationships between the bands by their colors.
PC Displays
ERDAS IMAGINE for Microsoft Windows NT supports the following visual type and pixeldepths:
• 8-bit PseudoColor
• 24-bit TrueColor
8-bit PseudoColor
An 8-bit PseudoColor display for the PC uses the same type of colormap as the X Windows 8-bit PseudoColor display.
24-bit TrueColor
A 24-bit TrueColor display for the PC assigns colors the same way as the X Windows 24-bit TrueColor display.
Displaying Raster Layers
Continuous Raster Layers
An image file (.img) can contain 3 continuous raster layers; Therefore, when displaying an image file with continuous raster layers, it is possible to assign which layers (bands) are to be displayed with each of the three color guns.
Band assignments are often expressed in R,G,B order. E.g.
• Landsat TM—natural color: 3, 2, 1
• Landsat TM—color-infrared: 4, 3, 2
• SPOT Multispectral—color-infrared: 3, 2, 1
谷歌地球历史影像80年代的高分影像是怎么来的？
5个免费的历史图像查看器可以重温过去
当您想跳回时空，看看您的后院如何变化时……
您可以在哪里以直观，用户友好的地图查看器查看历史图像？
别无所求，因为这里有5个可追溯到过去的在线平台…
并探索地球上几乎任何地方的历史图像。
1个 Google地球专业版
历史图像Google地球
Google不仅是地址解析地址的全球领导者，而且您可以通过其历史时间滑块跳到过去。
从卫星到航空摄影，Google Earth Pro都能将整个世界掌握在您的手中。
首先，放大到您感兴趣的区域。单击时间滑块图标。现在，过去可以访问您的社区。您会根据缩略图知道可用的年份。
2 Esri的Wayback生活地图集
历史图像埃斯里·韦伯
最近，Esri将他们的最新作品发布到《世界生活地图集》中。基本上，这组地球收集了影响人们日常生活的重要地理信息。
例如，这包括诸如天气，交通，海拔，人口统计，海洋和城市系统之类的项目。
Esri的《 Wayback Living Atlas》是其大量地图的一部分，可让用户及时浏览历史图像。
仍处于入门阶段，他们的影像收藏正在增长，并逐渐发展成为地图历史学家必不可少的平台。
3 USGS LandLook
历史图像uss landlook
如果您想了解USGS收集的约700万张扫描的历史图像的庞大集合，请前往USGS Earth Explorer。我们有一个分步教程，介绍如何从USGS Earth Explorer下载图像。您的搜索标准将改为“空中图像”，而不是卫星图像。我最喜欢的一些是NAIP，DOQ和马赛克。
为了快速查看Sentinel-2和Landsat图像，USGS的“土地外观”可追溯到1999年。
首先，通过过滤日期，年份，云量和传感器来加载图像。
接下来，您可以播放视频以显示您的时间跨度中的每个场景。
最后，如果要将场景导出为PNG，GeoTIFF或JPG，则可以选择“导出”工具。
总体而言，USGS Land Look是搜索Sentinel-2和Landsat档案库中的历史图像的理想选择。
4 NASA世界观
历史图像世界观
NASA的Worldview具有600个全球全分辨率卫星图像图层。
尽管它们比此列表中的其他列表更粗糙。但从本质上讲，它们显示的是“现在”的整个地球。实际上，它会在观察后的三个小时内更新。
所以您可能会问：这不是历史图像，是吗？
您可以通过调整时间滑块来倒退时间，而不必使用当前日期（这是默认日期）。与习惯的无云图像不同，这是我们星球的真实面目。
5行星实验室
历史图像行星实验室
以下是有关Planet的几个很酷的事实：
他们是前美国国家航空航天局（NASA）科学家组成的团队，他们的业务建立在低成本，轻巧的微型卫星上。
他们是目前地球上最大的图像采集器，拥有175颗以上的卫星。
Planet提供“免费增值”服务，该服务可以追溯到2009年，为您提供您感兴趣地区的历史背景。
Planet的卫星群非常适合监视地球上的任何物体。例如，《星球故事》允许用户使用空间图像并在任何地方讲述自己的故事。
历史语境的航空正射影像
当您想要某个感兴趣的领域的历史背景时，有几种选择可以帮助您入门。
Google地球是一款移动和桌面应用程序，具有大量免费的历史图像。
Esri的Wayback Living Atlas提供了一个在线平台。它是免费的，并且越来越有历史图像。最后，对于普通用户而言，它变得越来越普遍。
最后，USGS，NASA和Planet的卫星星座提供了一种查看地球历史的替代方法。
跪求冰雹“冰川的一些英文资料~
glacier:
a slowly moving mass of ice
wordnet.princeton.edu/perl/webwn
A glacier is a large, long-lasting river of ice that is formed on land and moves in response to gravity. A glacier is formed by multi-year ice accretion in mountainous or sloping terrain. The glacier fringe is the area where the glacier has recently melted. There are two main types of glaciers: alpine glaciers, which are found in mountain terrains, and continental glaciers, which are associated with ice ages and can cover large areas of continents. …
en.wikipedia.org/wiki/Glacier
Ray Lloyd is a professional wrestler better known as Glacier from his days in World Championship Wrestling.
en.wikipedia.org/wiki/Glacier_(wrestler)
A huge mass of ice, formed on land by the compaction and recrystallization of snow, that moves very slowly downslope or outward due to its own weight.
Bodies of land ice that consist of recrystallized snow accumulated on the surface of the ground, and that move slowly downslope.
a large mass of ice (at least .1km^2) set in motion by the Earth\’s gravity, which is a result of accumulated snowfall with little snow melt.
A glacier is a slowly-moving river of snow and ice.
A very large body of ice moving slowly down a slope or valley or spreading outward on a land surface
A large mass of ice formed by compressed snow, which moves slowly under its own weight. Glaciers exist where, over a period of years, snow remains after summer\’s end and accumulates year after year.
[glay-sher]- glaciers are accumulations of snow, ice, air pockets, water and rock debris. They can fill valleys or entire continents (as in the case of Antarctica). They have enough mass to flow across a landscape, moving as little as a few feet per year, up to thousands of feet per year. Glaciers are found throughout the world in such places as Africa, New Zealand and Chile.
A large mass of ice and snow that forms in areas where the rate of snowfall constantly exceeds the rate at which the snow melts
Any field or stream of ice of land origin. It may be either active or stagnant.
a large mass of ice formed by the accumulation of falling snow that moves like a river
a large body of ice with definite lateral limits, which moves in a downslope direction due to its great mass, as in Alaska.
Accumulation of ice of atmospheric origin generally moving slowly on land over a long period.
A mass of land ice, formed by the further recrystallization of firn, flowing continuously from higher to lower elevations. This term covers all such ice accumulations from the extensive continental glacier to tiny snowdrift glaciers. Nearly all glaciers are classified according to the topographical features with which they are associated, for example, highland glacier, plateau glacier, piedmont glacier, valley glacier, cirque glacier. …
amsglossary.allenpress.com/glossary/browse
A thick mass of ice resulting from compacted snow that forms when more snow accumulates than melts annually.
interactive2.usgs.gov/learningweb/textonly/teachers/volcanoes_guide_glossary.htm
A large mass of snow and ice moving along Earth\’s surface.
a body of ice, consisting largely of recrystalized snow, that shows evidence of downslide movement due to its own weight.
a body of moving ice, usually at least 100 feet thick so that the ice crystals on the bottom deform to effect movement.
is a body of ice showing evidence of movement as reported by the presence of ice flowline, crevasses, and recent geologic evidence. Glaciers exist where, over a period of years, snow remains after summer\’s end.
Shown on the map by a white background (ice) and blue contour lines. One glacier is labeled in red, but six other glaciers or partial glaciers also appear on this map. These are all examples of cirque glaciers.
A mass of slow-moving ice formed from accumulated snowfalls.
A large mass of ice formed, at least in part, on land by the compaction and recrystallization of snow, moving slowly down slope or outward in all directions due to the stress of its own weight and surviving from year to year. The term \”glacier\” is usually, though not exclusively, confined to ice bodies that are constrained by valleys. Ice bodies that are continental in scale are usually called \”ice sheets\”.
Bodies of ice and compacted snow. Glaciers are formed with the termperature is too cold to allow accumulating snow to melt. The snow compacts and eventually the snow crystals change into granular ice crystals called firn. As the firn becomes buried under more accumulating snow, it changes into solid ice. The changes takes years to accomplish. There are two categories of glaciers: Alpine (which form on mountainsides) or ice sheets (which form on flat land). …
a huge mass of ice and snow which moves extremely slowly (inches per year); able to scrape off and move large amounts of earth.
A mass of ice with definite lateral limits, with motion in a definite direction, and originating from the compacting of snow by pressure.
A large mass of ice which persists throughout the year, and moves slowly downslope in a liquid manor by it\’s own weight. Glaciers are formed in areas where the winter snow doesn\’t have a chance to melt, and consecutive snowfalls accumulate and compress into ice.
hail:
acclaim: praise vociferously; \”The critics hailed the young pianist as a new Rubinstein\”
be a native of; \”She hails from Kalamazoo\”
call for; \”hail a cab\”
greet enthusiastically or joyfully
precipitation of ice pellets when there are strong rising air currents
enthusiastic greeting
precipitate as small ice particles; \”It hailed for an hour\”
wordnet.princeton.edu/perl/webwn
Hail is a type of graupel (a form of precipitation) composed of balls or irregular lumps of ice. It occurs when supercooled water droplets (remaining in a liquid state despite being below the freezing point, 0 °C/32 °F) in a storm cloud aggregates around some solid object, such as a dust particle or an already-forming hailstone. The water then freezes around the object. …
en.wikipedia.org/wiki/Hail
showery precipitation in the form of irregular pellets or balls of ice more than 5 mm in diameter, falling from a cumulonimbus cloud.
precipitation composed of chunks of ice that form atop cumulonimbus clouds and fall as soon as they become too heavy for the cloud updrafts to hold.
Precipitation in the form of transparent or partially opaque balls or irregular lumps of concentric ice. Hail is normally defined as having a diameter of 5 millimeters or more and is produced by thunderstorms.
A call to another vessel. Harbor – A safe, protected anchorage for docking and loading. Hatch – An opening in the deck, providing access to the space below. Head – This word is used in many ways in boating, the most important to those on board being \”toilet.\” Heading – The compass direction in which a vessel is pointed at any given moment. Head sea – Waves coming from the direction in which a vessel is heading. Helm – Where the steering wheel is located. …
Precipitation in the form of hard pellets of ice which fall from cumulo-nimbus clouds and are often associated with thunderstorms.
Precipitation composed of balls or irregular lumps of ice with diameters between 5 and 50 mm.
Pieces of hard, solid ice falling from clouds.
Precipitation in the form of balls or irregular lumps of ice, always produced by convective clouds, nearly always cumulonimbus. An individual unit of hail is called a hailstone. By convention, hail has a diameter of 5 mm or more, while smaller particles of similar origin, formerly called small hail, may be classed as either ice pellets or snow pellets. …
amsglossary.allenpress.com/glossary/browse
Precipitation in the form of balls or clumps of ice, produced by thunderstorms. Severe storms with intense updrafts are the most likely large hail producers.
Precipitation in the forms of lumps of ice that occur with some thunderstorms.
a frozen form of precipitation in which droplets reach the ground still frozen as ice. Individual droplets, or hailstones, can range in size from a grain of sand to a large cobble.
A type of frozen precipitation formed when rain droplets are lofted high into the atmosphere by strong updrafts repeatedly, adding new layers of ice with each up-and-down trip, until it is finally heavy enough to fall to the ground. Hail accompanies strong thunderstorms and is usually a summertime phenomenon.
wilstar.com/skywatch_glossary.htm
Balls of ice ranging in size from tiny peas to larger than orange size
australiasevereweather.com/photography/define2.htm
millimetric or larger precipitation particle of ice, formed by the accretion of ice crystals and rapidly freezing supercooled water droplets.
to call to another ship.
Pieces of ice that sometimes form in high clouds
Precipitation in the form of nearly spherical or jagged chunks of ice; often characterized by internal concentric layering. Hail is associated with thunderstorm cells that have strong updrafts and relatively great moisture content.
precipitation in the form of hard pellets of ice or hard snow.
Precipitation in the form of circular or irregular-shaped lumps of ice.
weather.ncbuy.com/glossary.html
ice balls that are formed by rain that is thrown by air currents back up into a thundercloud, were a layer of ice forms around it. Hail can make several trips back up into a cloud, were it is covered with another level of ice each time.
library.thinkquest.org/3805/glossary/gloss.htm
opaque balls of ice, almost always spherical. Hail occurs in all provinces, but most frequently in Saskatchewan and Alberta, where some areas can get as many as 10 storms a year.
members.tripod.com/~MitchellBrown/almanac/weather_glossary.html
Rain that has been frozen many times on its way to the ground, creating a lumpy ball of ice.
weathereye.kgan.com/cadet/disaster/glossary.html
To attempt to contact another boat or shore, either by voice or radio.
is precipitation of small balls or pieces of ice (hailstones) with a diameter ranging from 5 to 50 mm (1/2 to 2 inches) or sometimes more, falling either separately or fused into irregular lumps. Hailstones are composed, almost exclusively of transparent ice, or a series of transparent ice at least 1 mm (1/25 in.) in thickness, alternating with translucent layers. Hail is generally observed during heavy thunderstorms.
Balls of ice that grow in thunderstorm updrafts.
跪求美国犹他州大盐湖的英文介绍
The Great Salt Lake and its islands provide outstanding scenery and recreational opportunities in northern Utah. Sunsets over the lake can be breathtaking. Amazing red, orange, lavender and magenta hues slowly dissolve in the evening sky. The lake\’s turquoise waters attract sailors, its white sand beaches are popular with swimmers and sunbathers, and craggy outcroppings on Antelope Island and some shoreline areas draw hikers and mountain bikers.
The Great Salt Lake is one of the most asked-about tourist destinations in Utah. A remnant of the massive ancient Lake Bonneville, the lake is now landlocked and its waters are salty. It is the largest lake between the Great Lakes and the Pacific Ocean, and is the largest saltwater lake in the Western Hemisphere.
Legends abound about the lake. Early explorers thought the lake was an inland extension of the Pacific Ocean, or that a river connected the lake to the ocean. Some Indians and early settlers thought the lake was inhabited by a terrible monster with an enormous head. The lake and its legends are an intriguing part of Utah\’s landscape and history.
Recreation
Excellent views of the lake are available from:
Ensign Peak on the north edge of Salt Lake City
Bench areas in the cities of Bountiful, Centerville and Farmington
Trails on Antelope Island
Interstate 80 along the lake\’s south shoreline
Swimming and sunbathing are popular on the clean, white sand beaches at Antelope Island State Park. The salinity of the water averages about 12%, making it much saltier than the ocean. The water is so buoyant that people can easily float. Freshwater showers are available to rinse off after swimming.
Sailing is very popular on the lake and full-service marinas are available at Antelope Island and Great Salt Lake State Marina on the south shore. On overcast days, the horizon on the lake blends into the sky and the landscape takes on a surreal look: skimming sailboats and the lake\’s distant islands appear to float midair. However, the lake is shallow (average depth about 20 feet) and even moderate winds can cause rough water. Experience is needed to navigate the lake. Powerboats can also operate on the lake. Motors not rated for saltwater need to be flushed carefully after use. Many people also kayak on the lake.
Wildlife is abundant on Antelope Island and in the lake\’s shoreline marshes. Bison, antelope, deer, bobcats, coyotes, and elk roam freely on the island and are often seen by visitors. Bird watching is popular at many spots around the lake, including the federally managed Bear River Bird Refuge and the state\’s Farmington Bay Waterfowl Management Area. The lake\’s marshes attract large numbers of migratory birds. Duck and goose hunting is allowed in some areas and is usually very good.
Kayaking on the Great Salt Lake is a great way to see some of the areas that you normally wouldn\’t see. With 10,000 miles of shoreline it can be one of the most rewarding places to paddle in North America.
Mountain biking is popular on excellent trails on Antelope and Stansbury islands. These areas also offer excellent hiking.
Antelope Island also offers excellent facilities for picnicking and camping.
Fish live in the freshwater marshes and inlets, but no fish species can survive in the lake\’s salty water. Unique brine shrimp thrive in the lake; they are harvested and processed into fish food. Brine flies live on the lake\’s shorelines and can be annoying. They don\’t bite but often swarm around humans. Antelope Island beaches are relatively free of brine flies. Winds coming off the lake can carry a \”lake stench\” at some times of the year. Again, the odor is usually not a problem at Antelope Island.
History
The Great Salt Lake is actually the remainder of prehistoric Lake Bonneville, which covered some 20,000 square miles of land in what is now Utah, Nevada and Idaho some 10,000 to 30,000 years ago. The present lake is about 75 miles long and 35 miles wide, with a maximum depth of 33 feet. After a series of wet years, the lake\’s surface area may be much larger but it will be only a little bit deeper.
Water levels in the lake are far from constant. During its recorded low in 1963, some of the lake\’s 10 major islands became peninsulas. In 1983, when the lake reached its historic high, it flooded houses, farmland and the nearby freeway. Huge pumps were constructed to deposit excess water into Utah\’s west desert. The pumps were shut down in 1989.
Four rivers and numerous streams empty into the Great Salt Lake, carrying dissolved minerals. The lake has no outlet so these minerals are trapped. Continual evaporation concentrates the minerals. Several businesses extract table salt and other chemicals from the lake water.
Park Information
There are two Utah State Parks on the Great Salt Lake: Antelope Island State Park and Great Salt Lake State Park. Antelope Island offers clean beaches, a visitor center, marina, historic ranch house, bison and camping. The Great Salt Lake Park offers a marina and historic Saltair (which was a thriving resort in the early 1900s).
Getting There
The Great Salt Lake is located north and west of Salt Lake City. To reach Antelope Island, drive north on I-15 to Syracuse, then west on U-127, following the signs. A causeway has been built to allow automobile access to the island. Great Salt Lake State Park/Saltair Beach is about 16 miles west of Salt Lake City, along I-80.
美国大峡谷英文介绍
Grand Canyon
大峡谷
Gorge cut by the Colorado River, northwestern Arizona, U.S. Noted for its rock formations and coloration, it is about 0.1–18 mi (0.2–29 km) wide and extends from northern Arizona to Grand Wash Cliffs, near the Nevada border, a distance of about 277 mi (446 km). The deepest section, 56 mi (90 km) long, is within Grand Canyon National Park, which covers the river\’s length from Lake Powell to Lake Mead. The surrounding plateau is 5,000–9,000 ft (1,500–2,750 m) above sea level, and the canyon is in places more than a mile (1.8 km) deep. The national park, now containing 1,904 sq mi (4,931 sq km), was created in 1919. The former Grand Canyon National Monument, established in 1932, was added, with other lands, in 1975. In 1979 the Grand Canyon was designated a World Heritage site.
美国亚利桑那州西北部由科罗拉多河切成的峡谷，以其形态奇特、色彩斑斓著称。宽约0.2～29千米，从亚利桑那州北部延伸到内华达州边界附近的大瓦士崖，长约446千米。最深的一段在大峡谷国家公园内，长90千米，包括科罗拉多河从鲍威尔湖到米德湖之间一段。附近高原海拔1,500～2,750米，大峡谷有些地方深度超过1英里。大峡谷国家公园建于1919年，占地4,931平方千米。1932年建立的大峡谷国家保护区，在1975年和其他邻近地带一并列入大峡谷国家公园中。
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