Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Altitude shopping experience:

1. Compare - without doubt the biggest advantage that the Altitude offers shoppers today is the ability to compare thousands of Altitude at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Altitude? Wrong! If the Altitude is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Altitude then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Altitude? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Altitude and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Altitude wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Altitude then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Altitude site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Altitude, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Altitude, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

For other uses see Altitude (disambiguation)

Altitude is the elevation of an object from a known level or datum (plural: data). Common data are mean sea level and the surface of the WGS-84 geoid, used by GPS. In aviation, altitude is measured in Foot (unit of length). For non-aviation uses, altitude may be measured in other units such as metres or miles.

Atmospheric pressure decreases as altitude increases. This principle is the basis of operation of the pressure altimeter, which is an barometer#Aneroid barometers calibrated to indicate altitude instead of pressure. It is the fall in pressure that leads to a shortage of oxygen (Hypoxia (medical)) in humans on ascent to high altitude.

Altitude in aviation In aviation, the term altitude can have several meanings. It is a fundamental tenet of flight safety that both parties exchanging information concerning this topic are absolutely clear which definition is being used.

True altitude is the elevation above mean sea level. In UK aviation radiotelephony usage, the vertical distance of a level, a point or an object considered as a point, measured from mean sea level; this is referred to over the radio as altitude.(see QNH)
height is the elevation above a ground reference point, commonly the terrain elevation. In UK aviation radiotelephony usage, the vertical distance of a level, a point or an object considered as a point, measured from a specified datum; this is referred to over the radio as height, where the specified datum is the airfield elevation (see QFE)
Absolute altitude is the height of the aircraft above the terrain over which it is flying.
Indicated altitude is the reading on the altimeter.
Pressure altitude is the elevation above a standard datum plane (typically, 1013.2 millibars or 29.92" Hg and 15°C). Pressure altitude divided by 100 feet is referred to as the flight level; so when the altimeter reads 18,000 ft on the standard pressure setting the aircraft is said to be at "Flight level 180". Below FL180, altitudes are read in thousands, pronounced "one three thousand" for 13,000, "seven thousand" for 7,000 etc.
Density altitude is the altitude corrected for non-ISA International Standard Atmosphere (ISA) conditions at which the air density is unequal to ISA conditions. Aircraft performance depends on density altitude, which is affected by barometric pressure and temperature. On a very hot day, density altitude at an airport may be so high as to preclude takeoff, particularly for helicopters or a heavily loaded aircraft.

Altitude regions Mountain medicine recognizes three altitude regions:

High altitude = 1500 m – 3500 m (5000 – 11,500 ft)
Very High altitude = 3500 m – 5500 m (11,500 – 18,000 ft)
Extreme altitude = 5500 m – above

Travel to high altitudes leads to a range of medical problems, from the relatively mild symptoms of acute mountain sickness to the potentially fatal high altitude pulmonary oedema (HAPE) and high altitude cerebral oedema (HACE). These conditions are caused by the profound hypoxia associated with travel to high altitudes.

The Earth's atmosphere is divided into several altitude regions:

Troposphere — surface to 5 miles (8 km) at poles – 11 miles (18 km) at equator), ending at the Tropopause.
Stratosphere — Tropopause to 31 miles (50 km)
Mesosphere — Stratopause to 53 miles (85 km)
Thermosphere — Mesopause to 420 miles (675 km)
Exosphere — Thermopause to 6200 miles (10,000 km)

References

External links

Downloadable ETOPO2 Raw Data Database (2 minute grid)
Downloadable ETOPO5 Raw Data Database (5 minute grid)

See also

See also

Altitude