US Survey Feet (ft-us) to Kilometers (km) conversion

What is us survey feet?

What is US Survey Feet?

US Survey Feet is a unit of length used in the United States for land surveying. It is slightly different from the international foot. Understanding its origin and applications is crucial for accurate land measurements and legal descriptions.

Origin and Definition

The US Survey Foot (ftUS) is defined based on the Mendenhall Order of 1893, which related customary units to the metric system using the meter. At that time, it was defined as:

1 US Survey Foot = $\frac{3937}{1200}$ meters

This value equates to approximately 0.3048006096 meters. This differs slightly from the international foot which is exactly 0.3048 meters. The difference, while seemingly small (2 parts per million), can accumulate significantly over large distances, impacting land boundaries and area calculations.

The Issue & Readjustment

The difference between the international foot and the US survey foot caused discrepancies, especially in states that relied heavily on the Public Land Survey System (PLSS). Over time, states have addressed this issue in various ways:

• Many states have officially adopted the international foot for all new surveys.
• Some states continue to use the US Survey Foot. It's crucial to know which definition is in use for any particular survey or land description.
• Conversion factors are often provided in legal documents to clarify which foot is being used.

For more information about each state's definitions of feet, please read NOAA's definition of US Survey foot.

Usage and Real-World Examples

While its use is declining, the US Survey Foot is still relevant in some contexts, especially when dealing with older surveys and legal descriptions. Understanding its magnitude helps grasp spatial relationships:

• Property Boundaries: In states where it is still used, a land description stating a lot is 100 US Survey Feet wide means it is approximately 30.48006096 meters wide.
• Land Area Calculations: Area calculations, like acres, derived from measurements in US Survey Feet will differ slightly from those derived from international feet.
• Geographic Information Systems (GIS): GIS databases may contain data referenced to US Survey Feet, requiring proper transformation when integrating with data using the international foot.

Interesting Facts

• The slight difference between the two definitions of a foot has caused legal disputes related to property boundaries.
• The National Geodetic Survey (NGS) provides tools and resources for converting between the US Survey Foot and the international foot.

What is kilometers?

Kilometers are a commonly used unit for measuring distances. Here's some information about them.

Kilometer Defined

A kilometer (km) is a unit of length in the metric system, equal to 1000 meters. It is widely used around the world for measuring distances between geographical locations, lengths of roads, and athletic distances.

Origin and Formation

The metric system, from which the kilometer is derived, was created in France in the late 18th century. The meter was initially defined as one ten-millionth of the distance from the equator to the North Pole along a meridian. The prefix "kilo-" comes from the Greek word "chilioi," meaning thousand. Therefore, a kilometer is simply one thousand meters.

The relationship between kilometers and meters is:

$1 \text{ km} = 1000 \text{ m}$

Notable Associations

While no specific law or person is uniquely tied to the kilometer itself, the broader development of the metric system involved many scientists and mathematicians of the time. The standardization and adoption of the metric system significantly aided scientific progress and international trade.

Real-World Examples

• Distances between Cities: The distance between New York and Los Angeles is approximately 3,944 kilometers.

• Road Lengths: Highway systems and major roads are often measured and marked in kilometers. The Pan-American Highway, for instance, stretches over 30,000 kilometers.

• Athletic Events: Long-distance running races often involve distances measured in kilometers, such as 5k (5 kilometers), 10k (10 kilometers), and marathons (approximately 42.2 kilometers).

• Geographic Features: The length of rivers, mountain ranges, and other geographical features are commonly described in kilometers. For example, The length of Nile river is approximately 6,650 kilometers.

• Altitude: While altitude is often measured in meters, higher altitudes such as the height of commercial airliners can be specified in kilometers. Commercial airlines usually fly between 9 to 13 kilometers.

Conversions to Other Units

• To miles: $1 \text{ km} \approx 0.621371 \text{ miles}$

• To feet: $1 \text{ km} \approx 3280.84 \text{ feet}$

• To inches: $1 \text{ km} \approx 39370.1 \text{ inches}$