A league
************************
That's a very old term!
Nautical miles
The milibar is a unit of pressure used in meteorology and is equal to one thousandth of a bar, which is roughly equal to atmospheric pressure at sea level. It is commonly used to measure air pressure in weather reports and forecasts.
In chemistry, atm stands for atmosphere, which is a unit of pressure equal to the average air pressure at sea level (approximately 1 atm). It is commonly used to measure gas pressure in laboratory experiments.
The instrument used to measure elevation is called an altimeter. It works by measuring air pressure changes as altitude changes, providing a rough estimate of elevation above sea level.
A kilogram is a measure of weight. A gallon is a measure of liquid volume. You cannot convert one to the other. You can, however, convert gallons to liters. 9 gallons is equal to 34.06871 liters. Actually a kilogram is a measure of mass. A kilogram at sea-level weighs 9.8 Newtons. Also at sea level a kilogram has a weight of 2.2 pounds.
Something on land can be measured as below sea level when its elevation is lower than the average level of the world's oceans. This can be determined using a reference point, such as sea level, to calculate the vertical distance below it. Topographic maps and GPS technology are commonly used to measure elevations above and below sea level.
A kilometre. A megametre may be more appropriate but it is not a unit that is used much.
Degrees Celsius measure temperature. It is a unit of measurement typically used to express temperatures in the Celsius scale, which is based on the freezing and boiling points of water at sea level.
miles
The milibar is a unit of pressure used in meteorology and is equal to one thousandth of a bar, which is roughly equal to atmospheric pressure at sea level. It is commonly used to measure air pressure in weather reports and forecasts.
In chemistry, atm stands for atmosphere, which is a unit of pressure equal to the average air pressure at sea level (approximately 1 atm). It is commonly used to measure gas pressure in laboratory experiments.
Its height (above mean sea level): metres Its length: kilometres - or metres if it is a really short trail.
Traditionally the unit is the fathom (=6 feet) but nowadays you will see metres or indeed any proper unit of length.
The instrument used to measure elevation is called an altimeter. It works by measuring air pressure changes as altitude changes, providing a rough estimate of elevation above sea level.
The measure of how high a place is above sea level is called elevation.
Sea level is a standard 'height' from which you can measure the relative height of objects (ie. cities) as such, high above sea level would refer to something 1,000+ metres above sea level... or whatever definition you think appropriate.
Use positive numbers for altitudes above sea level, zero is sea level itself, and negative numbers for altitudes below sea level. As for the picture, use a number line - but make vertical instead of using the commonly used horizontal position.
metres above the mean sea level