3 July 2007



  • 1630 - A man named Beaumont laid rails on a highway in England to transport coal from the Newcastle mines. This is the first railroad known in history.
  • 1765 - James Watt constructed his first steam engine at the Corson Iron Works, Glasgow, Scotland.
  • 1776 - The first iron rails, of which we have a complete account, were cast with a perpendicular ledge instead of the flange on modern wheels.
  • 1801 - A short line of track for a horse railroad was laid between Wandsworth and Croydon in the suburbs of London - the first chartered railroad on record.
  • 1804 - The first attempt to utilize steam power on a railroad was made by a Cornishman named Trevithick, who ran a locomotive attached to several wagons in South Wales.
  • 1827 - The first American railroad, from Quincy, Massachusetts, to the Neponset River, was completed.
  • 1828 - Charles Carroll, the last surviving signer of the Declaration of Independence, laid, on July 4, the first rail of the Baltimore and Ohio Railroad.
  • 1829 - The Stourbridge Lion, the first steam locomotive ever seen in America, had its trial trip over the line of the Delaware and Hudson Canal and Railroad Company. In England, Stephenson's locomotive, The Rocket, won the prize of $2,500 offered by the directors of the Liverpool and Manchester Railway.
  • 1830 - The first section of the Baltimore and Ohio Railroad, fifteen miles in length, was opened. Over it Peter Cooper ran his little locomotive, Tom Thumb, to prove that engines could be used on curves. The Best Friend, the first locomotive built in America for actual service, began regularly to haul freight on the South Carolina Railroad.
  • 1842 - The whole of the Boston and Albany was completed, the first road to be operated as an important through route. The New York Central route to Buffalo was opened, though the various companies along the line were not consolidated until eleven years later.
  • 1844 - With the aid of the government, Professor Morse built his pioneer telegraph line between Baltimore and Washington.
  • 1846 - The Pennsylvania Railroad was chartered.
  • 1853 - Eleven railroads were consolidated into the New York Central.
  • 1854 - The Mississippi River was first reached by the Chicago and Rock Island Road.
  • 1858 - Railroad building was pushed as far West as the Missouri River, the Hannibal and St. Joseph reaching that river.
  • 1868 - George Westinghouse invented the air-brake.
  • 1869 - The Union and Central Pacific lines were joined, making a through railroad route from the Atlantic to the Pacific.
  • 1870 - The Chicago and Omaha pool was formed, the first pool on a large scale in the history of American railroading.
  • 1887 - The Interstate Commerce Commission was established to have supervision over railroad rates.
  • 1901 - The Northern Securities Company was organized to control the transcontinental railroads.
  • 1904 - The United States Supreme Court, by a decision of five to four, held that the Northern Securities Company was in restraint of trade and was therefore illegal.
  • 1906 - The Hepburn bill was passed by Congress, increasing the size and powers of the Interstate Commerce Commission.

28 June 2007

EXODUS3000:A Game for Earning

Upgrade, attack, defend, form alliances, and earn real cash and win prizes.

This is note on this gaming site. I think most of u have got it. For those who didn't I'll tell u in the simple words.
This is an strategy game where you are supposed to be in Mars.When you sign up and enter the game you will see Homebase with the four directions N, E,S and W. When you click on these you'll enter another zone like Volcano,where it's written mine the volcano.When you click on mine this volcano you'll earn Mars dollars in short MDs. With these you can upgrade your defense,Weopons,scouts,security and even radar. Similarly,there are zones like Ruins,Craters,Plains,etc.Most important the payouts.You can sell your MDs for $ according to the payouts.That's secondary I suppose. Newly upgraded cards even add to the exitement. So what are you waiting for? Come join us
Enjoy,Play and Earn.

27 June 2007


Nokia E90
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The world's largest mobile-phone maker launched the second generation of its successful E-series business phones at the 3GSM trade show in Barcelona . Leading the trio is the E90 Communicator, a mini computer with support for Wi-Fi and HSDPA-enhanced 3G with integrated GPS and route mapping.
A worthy successor to the previous Communicator 9500 which was launched over two years ago, E90 Communicator comes with a 4-inch wide screen that allows full-width Web browsing for the first time. It also features integrated GPS to allow turn-by-turn navigation.
The phone that could work as a phone, entertainment device and videoconferencing tool, will also offer an FM radio, a music player, a video player and two cameras -- a 3.2 megapixel one with flash and a second camera for video conferencing.
First deliveries of phone are expected during the second quarter of 2007, with global availability during the third quarter of this year.

Nokia N77

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Another big launch from the company is N77 -- its first mid-priced mobile-TV phone (its second so far). The phone will be able to receive TV signals broadcast in DVB-H (Nokia?s own TV technology platform). While Nokia and other European phone makers favour the homegrown DVB-H technology for watching broadcasts on cellphones, rival formats such as MediaFlo from Qualcomm and DMB are getting there too.
The N77 features a wide 2.4-inch screen, high-quality stereo sound and alerts when programmes are about to start. However, the Nokia N77 is much more than just live TV. Designed to work on 3G (WCDMA 2100 MHz), EDGE and GSM (900/1800/1900 MHz) networks, Nokia N77 is based on S60 3rd Edition software on Symbian OS.
The N77, which will start shipping in the second quarter, will cost 370 Euros ($480), roughly half the price of the N92.

Mobile Ameo

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Here comes a phone with a hard drive. T-Mobile (a unit of Deutsche Telekom and one of the operators in Germany ) has unveiled a phone with a hard disk disk (HDD), saying the pocket-sized device with a 13-centimetre screen would go on sale in Germany just before Cebit show in March.
Called Ameo, the phone contract manufactured by HTC uses Microsoft's operating system Windows Mobile 5.0. It would cost about 500 euros ($650) bundled with two years of phone service.
It has a 8 GB HDDD and looks more like a mini laptop. Its best feature is its detachable 13-centimetre wide keyboard and upright display. However, T-Mobile has no immediate plans to sell it in the US or rest of Europe .

BlackBerry 8800

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Barely eight months after it introduced its first feature-rich multimedia device Pearl , Research In Motion has decided to give a Pearl-like finish to some other handsets. It has debuted another Pearl look-alike device 8800, a full-keyboard model that can play music and videos, besides handling e-mails as efficiently as ever. The company is billing the 8800 as the thinnest BlackBerry to date, measuring 0.55 inches from front to back.
New features include an instant-messaging client that can chat to buddies on Yahoo IM and Google Talk, plus RIM's own browser. The 8800 also comes with a media player and an external storage slot for removable microSD memory cards.
Above all, it uses a GPS chipset for mapping and navigation that finds its way in a BlackBerry device for the first time and will compete with Nokia's 6110 Navigator phone. RIM has partnered with California-based navigation solutions firm TeleNav, which also offers similar versions of the software for Windows Mobile, the Palm operating system, Symbian, Qualcomm's Brew, and the Java-based J2ME environment from Sun Microsystems. So the advantage to RIM could only be temporary.
Besides, the 8800 is among the new crop of handsets that some feel could also bite into Apple iPhone's marketshare somewhat.

HP iPAQ 500

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Another big launch at 3GSM World Congree 2007 was the Hewlett-Packard iPaq 500 smartphone. Hewlett Packard unveiled its first smart phone, a slimmed-down iPaq that will be among the first Windows Mobile 6 handsets when it launches by second quarter this year.
The 500 series will be the first iPaqs that look like cellphones, with phone keypads instead of QWERTY keyboards or touch screens and styli. iPaq 500 comes with VOIP compatibility, push e-mail, Microsoft Internet Explorer and Outlook Mobile. The phone features 1.3-megapixel camera, Bluetooth, 64MB of memory and 128MB of storage with a micro SD card slot to expand memory.
The iPaq 500 connects to the Internet via GSM/GPRS/Edge networks, as well as via Wi-Fi. The handset also allows users to play music and videos, store photos and play games on the device.

Samsung Ultra Smart F700

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If Nokia has kicked so much dust in Barcelona , could Samsung be far behind? With its newest handset Ultra Smart F700, the
Korean giant has joined Apple and its arch-rival LG into the club of touchscreen mobile phones manufacturers.
The phone is Samsung's first that is compatible with 3G (third generation) WCDMA (Wideband Code Division Multiple Access) in addition to GSM (Global System for Mobile Communications) . It also works with HSDPA and EDGE data transmission systems on 3G networks and can receive data at up to 7.2Mbps (bits per second).
The phone features a 2.8-inch 440x240 screen to control calling, Internet access, and music functions. Media playback support includes multiple AAC audio formats, Real, and variants of MPEG-4 including H.264.
It also includes VibeTonz, a vibration system introduced in the recent W559 that simulates tactile feedback to touchscreen presses. And unlike Apple's iPhone, where typing on a small screen with your thumbs can leave you sore, F700 includes a slide-out keyboard to accommodate typing.
And that is not all! The phone has a 5-megapixel camera with auto-focus that is far superior than iPhone's meager 2-megapixel offering. But of course, it has a microSD slot that will help expand the memory you would require for storing the humongous 5 MP photos, and music.

Apple iPhone

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The iPhone, which has no conventional buttons, instead uses a large touch-screen. The firm has patented keyboard technology on the 11.6 mm thick phone calling it "multi-touch" . The 3.5 inch touch-screen- controlled device plays music, surfs the Internet and delivers voice mail and email differently.
The iPhone comes with a built-in, 2 MP digital camera as well as a slot for headphones and a SIM card. It runs Apple's OS X operating system, and has the Safari browser for Web access. The handset dispenses with buttons altogether, in favour of a powerful screen that responds to touch. It has a proximity sensor that automatically deactivates the screen and turns off the touch sensor when the device is raised to a user's face.
Music is automatically muted when a phone call comes in. The phone will play videos in widescreen format and automatically senses whether the screen is being held vertically or horizontally.
Has built-in Wi-Fi and Bluetooth and includes free BlackBerry-style 'push' email service from Yahoo. Apple is partnering with Yahoo Inc. on Web-based email and Google Inc on maps. To make a call, users can tap out the number on an on-screen keypad or scroll through their contacts and dial with a single touch. To zoom in on a photo or Web site, tap twice. To zoom out, tap once with two fingers.

LG Prada

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This is the phone for which the maker LG Electronics has officially accused Apple of copying the design for its newly launched iPhone last month.
LG Electronics and PRADA unveil the first completely touch screen mobile phone. The PRADA Phone by LG introduces the world?s first advanced touch interface which eliminates the conventional keypad. The phone comes with 3.0-inch display and Bluetooth 2.0 and a 2 megapixel camera featuring Schneider-Kreuznach lens and LED flash. It also features a player supporting MPEG4, H.264, a document viewer and an audio player with support for MP3/ACC/ACC+ /WMA/RA format.
The PRADA Phone by LG will be available with prices starting from 600 Euros at selected PRADA stores in the UK , France , Germany and Italy by the end of this month, followed by countries in Asia such as Hong Kong , Taiwan , and Singapore by late March.

Motorola Rizr Z8

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Motorola, the world's second-biggest mobile phone maker introduced a new phone design, which slides open and bends to bring the microphone closer to the user's mouth. The Rizr Z8, unveiled at the 3GSM wireless trade show in Barcelona, uses software from Symbian, which specializes in advanced cellphones and is more often found in phones from Nokia, Motorola's bigger rival.
The new high-speed wireless Rizr Z8 slides open to reveal a keyboard and, unlike traditional sliders, it has an automatic hinge that tilts the keyboard and locks the phone into a V-shape to make it easier to talk into.
The Rizr Z8 will also support television-quality video playback and has a slot for a memory card with up to 4 gigabytes of storage space. The product will be Motorola's fourth phone based on Symbian technology.

Nokia N6110

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One of the hottest buzzwords in the mobile industry since sometime has been: Location-based services. The services primarily allow people to view where they are on a map, search for points-of-interests (POI) around them and create routes to get them there free of charge. However, navigation by mobile phone has been slow to catch on. Courtesy, small phone screens, short battery life and the directions and maps that often lacked accuracy.
Taking a cue, the world?s biggest cellphone manufacturer Nokia unveiled its first mass market navigation-enabled phone, the N6110 Navigator. The launch unwraps company's plans to make a big push in location-based services.
Nokia 6110 Navigator is a GPS-enabled mobile phone that features integrated maps and turn-by-turn directions with voice guidance and turn arrows pointing users in the appropriate direction. The Nokia 6110 Navigator can also provide users with traffic information, weather services and travel guides. According to a company spokesperson, Nokia would launch "a number" of navigation devices in 2007.

26 June 2007


SE K530 with GPS

K530 does GPS as well
Looks like Sony Ericsson will be jumping aboard the GPS bandwagon with its K530 handset. This GPS navigation capable cellphone is the first from Sony Ericsson's stable to do so, boasting full point-to-point navigation. Not only do you get help in knowing where to go, the K530 also delivers weather forecasts for your current location if the need arises. The K530 is also supports 3G connectivity, letting your surf the Internet and catch up on the latest news via a RSS reader. Other features include a 2 megapixel camera, 16MB of internal memory, and a Memory Stick Micro memory card slot. There is no word on pricing details, but the K530 will hit the streets when Q3 2007 rolls around.

Symbol Technologies announce MC35

Symbol Technologies announce MC35

Symbol Technologies has recently announced the MC35 Pocket PC phone that comes in a form factor which is similar to that of a PDA, featuring a whole host of connectivity options to keep you abreast with the latest happenings within the company. Each MC35 comes with built-in WiFi and Bluetooth connectivity, and integrated GPS navigation system, push email support, and the ability to access AT&T's high-speed wireless data network. The inclusion of Push-To-Talk functionality also helps you save money in the long run, especially when you need to communicate with colleagues and underlings who are on-site.

NOKIA N95 with GPS
Nokia N95 on sale in US

Those hankering after the Nokia N95 will be pleased to know that this "portable computer" is now up for sale in the U.S. across various Nokia Flagship stores, online, and selected wireless retailers. To give you an idea of what $749 can give you, the N95 boasts a 2-way slide design for different modes, WiFi, GPS, and Bluetooth connectivity, a 5 megapixel camera featuring Carl Zeiss optics, video recording, a TV-out port, a microSD memory card slot, integrated stereo speakers, and a 3.5mm stereo headset port among others.


PalmNavi F3501 GPS navigation system

The PalmNavi F3501 GPS navigation system was recently paraded at Computex 2007, and what you get is a fairly normal GPS navigation system. Features include a 3.5" touchscreen display, 3D graphics that make it easier to determine where your exact location is, and a 1800mAh li-ion battery that provides up to 8 hours of juice. A flip up GPS antenna produces superior reception, while MP3 and MPEG 4 support ensures you won't run out of entertainment options when going through the motions of a long road trip.


SONY ERICSSON K850 with 5MP Camera

SONY ERICSSON has announced the Cybershot K850 camera phone that comes with a mind-blowing 5MP camera with autofocus that includes a real xenon flash, a dedicated shutter button, and the ability to record QVGA video at 30fps. This photo-centric handset also boasts Sony Ericsson's BestPic multi-shot capability in addition to the Photo Fix system that adjusts photo brightness levels with a single click. In addition, the K850 also supports quad-band GSM/EDGE/HSDPA, and offers MP3 playback, 40MB of memory, and the option to upgrade the memory through the help of M2 or microSD cards.Sounds like a pretty solid handset on all accounts.


22 June 2007

Applications of GIS

A color photograph of cave drawing.

Figure 1. Group of stags (cave painting), Lascaux Caves, France (Art Resources, N.Y.).

GIS through history

Some 35,000 years ago, Cro-Magnon hunters drew pictures of the animals they hunted on the walls of caves near Lascaux, France, (fig. 1). Associated with the animal drawings are track lines and tallies thought to depict migration routes. These early records followed the two-element structure of modern geographic information systems (GIS): a graphic file linked to an attribute database.

An outline map with lines indicating pathways.

Figure 2. Tracks of caribou routes in Alaska from April 1985 to December 1986 (U.S. Fish and Wildlife Service).

Today, biologists use collar transmitters and satellite receivers to track the migration routes of caribou and polar bears to help design programs to protect the animals. In a GIS, the migration routes were indicated by different colors for each month for 21 months (fig. 2). Researchers then used the GIS to superimpose the migration routes on maps of oil development plans to determine the potential for interference with the animals.


Researchers are working to incorporate the mapmaking processes of traditional cartographers into GIS technology for the automated production of maps.

One of the most common products of a GIS is a map. Maps are generally easy to make using a GIS and they are often the most effective means of communicating the results of the GIS process. Therefore, the GIS is usually a prolific producer of maps. The users of a GIS must be concerned with the quality of the maps produced because the GIS normally does not regulate common cartographic principles. One of these principles is the concept of generalization, which deals with the content and detail of information at various scales. The GIS user can change scale at the push of a button, but controlling content and detail is often not so easy. Mapmakers have long recognized that content and detail need to change as the scale of the map changes. For example, the State of New Jersey can be mapped at various scales, from the small scale of 1:500,000 to the larger scale of 1:250,000 and the yet larger scale of 1:100,000 (fig.3a), but each scale requires an appropriate level of generalization (figs. 3b, c, and d).

Sections of different scale maps in black and white.

Figure 3a. Digital revision of 1:100,000-scale digital line graph data to produce a 1:500,000-scale New Jersey State base map. Paneling and generalization are shown in three stages from 1:100,000 scale to 1:250,000 scale to 1:500,000 scale.

Color line maps showing different scale maps.

Figure 3b, c, d. These digital maps of Bergen County, N.J. are all at the scale of 1:500,00. The information content of the maps has been reduced through the process of generalization in two stages, from 1:100,000 scale on the left to 1:250,000 in the center, then from 1:250,000 to 1:500,00 scale on the right.

Site selection

The U.S. Geological Survey (USGS), in a cooperative project with the Connecticut Department of Natural Resources, digitized more than 40 map layers for the areas covered by the USGS Broad Brook and Ellington 7.5-minute topographic quadrangle maps (fig. 4). This information can be combined and manipulated in a GIS to address planning and natural resource issues. GIS information was used to locate a potential site for a new water well within half a mile of the Somers Water Company service area (fig. 5).

A color map of Connecticut.

Figure 4. USGS digital line graph map of the State of Connecticut from 1:2,000,000-scale data. The Broad Brook and Ellington 7.5-minute quadrangle areas are outlined in black in the upper middle.

A color outline and shape map of the water service area.

Figure 5. Map of the areas covered by the Broad Brook and Ellington 7.5-minute quadrangle showing the Somers Water Company service area at the scale of 1:24:000.

To prepare the analysis, cartographers stored digital maps of the water service areas in the GIS. They used the proximity function in the GIS to draw a half-mile buffer zone around the water company service area (fig. 6). This buffer zone was the "window" used to view and combine the various map coverages relevant to the well site selection.

A colored line map of water service buffer zone.

Figure 6. Enlarged view of figure 5 showing a half-mile buffer zone drawn around the service area of the Somers Water Company

The land use and land cover map for the two areas shows that the area is partly developed (fig. 7). A GIS was used to select undeveloped areas from the land use and land cover map as the first step in finding well sites. The developed areas were eliminated from further consideration (fig. 8).

An outline map showing with colored areas showing land use.

Figure 7. Land use and land cover data for the area bounded by a half-mile buffer zone around the water company service area.

An outline map showing selected areas of land use.

Figure 8. Land use and land cover data shown in figure 7 have been reselected to eliminate developed areas.

The quality of water in Connecticut streams is closely monitored. Some of the streams in the study area were known to be unusable as drinking water sources. To avoid pulling water from these streams into the wells, 100-meter buffer zones were created around the unsuitable streams using the GIS, and the zones were plotted on the map (fig. 9). The map showing the buffered zones was combined with the land use and land cover map to eliminate areas around unsuitable streams from the analysis (fig. 10). The areas in blue have the characteristics desired for a water well site.

Map lines showing buffer zones.

Figure 9. Buffer zones of 100 meters are drawn around polluted stream in the water service area.

Map shapes showing buffer zones.

Figure 10. Buffered streams shown in figure 9 area subtracted from areas previously selected with the land use and land cover data.

Point sources of pollution are recorded by the Connecticut Department of Natural Resources. These records consist of a location and a text description of the pollutant (fig. 11). To avoid these toxic areas, a buffer zone of 500 meters was established around each point (fig. 12). This information was combined with the previous two map layers to produce a new map of areas suitable for well sites (fig. 13).

Map points with numbers 1 through 6.

Figure 11. Points sources of pollution in the water service area are identified and entered into a GIS.

Mapped circles.

Figure 12. Buffer zones of 500 meters are drawn around the point sources of pollution.

Mapped shapes showing buffer zones.

Figure 13. A new map is created in a GIS by eliminating the buffered sources of pollution from the previously selected areas shown in figure 10.

The map of surficial geology shows the earth materials that lie above bedrock (fig. 14). Since the area under consideration in Connecticut is covered by glacial deposits, the surface consists largely of sand and gravel, with some glacial till and fine-grained sediments. Of these materials, sand and gravel are the most likely to store water that could be tapped with wells. Areas underlain by sand and gravel were selected from the surficial geology map (fig. 15). They were combined with the results of the previous selections to produce a map consisting of: (1) sites in underdeveloped areas underlain by sand and gravel, (2) more than 500 meters from point sources of pollution, and (3) more than 100 meters from unsuitable streams (fig. 16).

A map with color areas denoting geology.

Figure 14. Map of surficial geology of the water service area.

A map with color overlay.

Figure 15. Selection areas of sand and gravel from the map of surficial geology.

Mapped shapes showing sand and gravel areas.

Figure 16. Map produced by combining the areas composed of sand and gravel with previous selection from figure 13.

A map that shows the thickness of saturated sediments was created by using the GIS to subtract the bedrock elevation from the surface elevation (fig. 17). For this analysis, areas having more than 40 feet of saturated sediments were selected and combined with the previous overlays.

A map with color overlays showing differences in surface.

Figure 17. A bedrock elevation subtracted from surface elevation by a GIS to show the thickness of water-saturated sediment.

A color area map with shapes representing the thicker areas.

Figure 18. Potential sites with saturated thickness of sediments greater than 40 feet.

The resulting site selection map shows areas that are undeveloped, are situated outside the buffered pollution areas, and are underlain by 40 feet or more of water-saturated sand and gravel (fig. 18). Because of map resolution and the limits of precision in digitizing, the very small polygons (areas) may not have all of the characteristics analyzed, so another GIS function was used to screen out areas smaller than 10 acres. The final six sites are displayed with the road and stream network and selected place names for use in the field (fig. 19).

A color line and shape map showing named features.

Figure 19. Potential water well sites, roads, streams and place names.

The process illustrated by this site selection analysis has been used for many common applications, including transportation planning and waste disposal site location. The technique is particularly useful when several physical factors must be considered and integrated over a large area.

Emergency response planning

The Wasatch Fault zone runs through Salt Lake City along the foot of the Wasatch Mountains in north-central Utah (fig. 20).

A color shaded relief map.

Figure 20. Map of the area surrounding the USGS Sugar House 7.5-minute quadrangle, Salt lake City, Utah, showing the location of the Wasatch Fault zone.

A GIS was used to combine road network and earth science information to analyze the effect of an earthquake on the response time of fire and rescue squads. The area covered by the USGS Sugar House 7.5-minute topographic quadrangle map was selected for the study because it includes both undeveloped areas in the mountains and a part of Salt Lake City. Detailed earth science information was available for the entire region.

The road network from a USGS digital line graph includes information on the types of roads, which range from rough trails to divided highways (fig. 21). The locations of fire stations were plotted on the road network. A GIS function called network analysis was used to calculate the time necessary for emergency vehicles to travel from the fire stations to different areas of the city. The network analysis function considers two elements: (1) distance from the fire station, and (2) speed of travel based on the type of road. The analysis shows that under normal conditions, most of the area within the city will be served in less than 7 minutes and 30 seconds because of the distribution and density of fire stations and the continuous network of roads.

The accompanying illustration (fig. 22) depicts the blockage of the road network that would result from an earthquake, assuming that any road crossing the fault trace would become impassable. The primary effect on emergency response time would occur in neighborhoods west of the fault trace, where travel times from the fire stations would be noticeably lengthened.

A color line map showing access times prior to faulting.

Figure 21. Before faulting. Road network of area covered by the Sugar House quadrangle plotted from USGS digital line graph data, indicating the locations of fire stations and travel times of emergency vehicles. Areas in blue can receive service within 2½minutes, area in green within 5 minutes, areas in yellow within 7½ minutes, and areas in magenta within 10 minutes. Areas in white cannot receive service within 10 minutes.

A color line map showing access times after faulting.

Figure 22. After faulting, initial model. Network analysis in a GIS produces a map of travel times from the stations after faulting. The fault is in red. Emergency response times have increased for areas west of the fault.

The Salt Lake City area lies on lake sediments of varying thicknesses. These sediments range from clay to sand and gravel, and most are water-saturated. In an earthquake, these materials may momentarily lose their ability to support surface structures, including roads. The potential for this phenomenon, known as liquefaction, is shown in a composite map portraying the inferred relative stability of the land surface during an earthquake. Areas near the fault and underlain by thick, loosely consolidated, water-saturated sediments will suffer the most intense surface motion during an earthquake (fig. 23). Areas on the mountain front with thin surface sediments will experience less additional ground acceleration. The map of liquefaction potential was combined with the road network analysis to show the additional effect of liquefaction on response times.

The final map shows that areas near the fault, as well as those underlain by thick, water-saturated sediments, are subject to more road disruptions and slower emergency response than are other areas of the city (fig. 24).

A color shape and line map showing liquefaction regions.

Figure 23. Map of potential ground l liquefaction during an earthquake. The least stable areas are shown by yellows and oranges, the most stable by grays and browns.

A color line map showing final travel time after faulting.

Figure 24. After faulting, final model. A map showing the effect of an earthquake on emergency travel times is reduced by combining the liquefaction potential information from figure 23 with the network analysis from figure 22.

Three-dimensional GIS

To more realistically analyze the effect of the Earth's terrain, we use three-dimensional models within a GIS. A GIS can display the Earth in realistic, three-dimensional perspective views and animations that convey information more effectively and to wider audiences than traditional, two-dimensional, static maps. The U.S. Forest Service was offered a land swap by a mining company seeking development rights to a mineral deposit in Arizona's Prescott National Forest. Using a GIS, the USGS and the U.S. Forest Service created perspective views of the area to depict the terrain as it would appear after mining (fig. 25).

 A line map of surface elevations.

Figure 25. Prescott National Forest, showing altered topography due to mine development.

To assess the potential hazard of landslides both on land and underwater, the USGS generated a three-dimensional image of the San Francisco Bay area (fig. 26). It created the image by mosaicking eight scenes of natural color composite Landsat 7 enhanced thematic mapper imagery on California fault data using approximately 700 digital elevation models at 1:24,000 scale.

A color photo map with lines showing avalanche areas.

Figure 26. Three-dimensional image of the San Francisco Bay created to assess the potential of land and underwater avalanches.

Graphic display techniques

Traditional maps are abstractions of the real world; each map is a sampling of important elements portrayed on a sheet of paper with symbols to represent physical objects. People who use maps must interpret these symbols. Topographic maps show the shape of the land surface with contour lines. Graphic display techniques in GISs make relationships among map elements more visible, heightening one's ability to extract and analyze information.

Two types of data were combined in a GIS to produce a perspective view of a part of San Mateo County, Calif. The digital elevation model, consisting of surface elevations recorded on a 30-meter horizontal grid, shows high elevations as white and low elevations as black (fig. 27). The accompanying Landsat thematic mapper image shows a false-color infrared image of the same area in 30-meter pixels, or picture elements (fig. d). A GIS was used to register and combine the two images to produce the three-dimensional perspective view looking down the San Andreas Fault (fig. 29).

A color picture showing DEM.

Figure 27. Digital elevation model of San Mateo County, Calif.

A color Landsat photograph.

Figure 28. Landsat Thematic Mapper image of San Mateo County, Calif.

A color perspective view.

Figure 29. Perspective view of San Mateo County, Calif.


Maps have traditionally been used to explore the Earth. GIS technology has enhanced the efficiency and analytical power of traditional cartography. As the scientific community recognizes the environmental consequences of human activity, GIS technology is becoming an essential tool in the effort to understand the process of global change. Map and satellite information sources can be combined in models that simulate the interactions of complex natural systems.

Through a process known as visualization, a GIS can be used to produce images— not just maps, but drawings, animations, and other cartographic products. These images allow researchers to view their subjects in ways that they never could before. The images often are helpful in conveying the technical concepts of a GIS to nonscientists.

Adding the element of time

The condition of the Earth's surface, atmosphere, and subsurface can be examined by feeding satellite data into a GIS. GIS technology gives researchers the ability to examine the variations in Earth processes over days, months, and years. As an example, the changes in vegetation vigor through a growing season can be animated to determine when drought was most extensive in a particular region. The resulting normalized vegetation index represents a rough measure of plant health (fig. 30). Working with two variables over time will allow researchers to detect regional differences in the lag between a decline in rainfall and its effect on vegetation. The satellite sensor used in this analysis is the advanced very high resolution radiometer (AVHRR), which detects the amounts of energy reflected from the Earth's surface at a 1-kilometer resolution twice a day. Other sensors provide spatial resolutions of less than 1 meter.

A color globe showing European area.

A color globe showing South America area.

Figure 30. One time slice of the vegetation index for part of the globe from AVHRR data.

Serving GIS over the Internet

Through Internet map server technology, spatial data can be accessed and analyzed over the Internet. For example, current wildfire perimeters are displayed with a standard web browser, allowing fire managers to better respond to fires while in the field and helping homeowners to take precautionary measures (fig. 31).

A color photo showing a pair of computer screen snapshots.

Figure 31. Wildfires burning for the past 24 hours accessible by means of a web browser and Internet map server GIS technology.

The future of GIS

Environmental studies, geography, geology, planning, business marketing, and other disciplines have benefitted from GIS tools and methods. Together with cartography, remote sensing, global positioning systems, photogrammetry, and geography, the GIS has evolved into a discipline with its own research base known as geographic information sciences. An active GIS market has resulted in lower costs and continual improvements in GIS hardware, software, and data. These developments will lead to a much wider application of the technology throughout government, business, and industry.

GIS and related technology will help analyze large datasets, allowing a better understanding of terrestrial processes and human activities to improve economic vitality and environmental quality.