Decimeters (dm) to US Survey Feet (ft-us) conversion

What is decimeters?

Decimeters are a unit of length, smaller than a meter, used in the metric system. Here's a breakdown of what decimeters are and their context:

Decimeter Definition

A decimeter (dm) is a unit of length in the metric system. "Deci" is a prefix meaning one-tenth, so a decimeter is one-tenth of a meter.

$$1 \text{ dm} = \frac{1}{10} \text{ m} = 0.1 \text{ m}$$

Formation and Relation to Other Units

The metric system is based on powers of ten, which makes conversions straightforward.

• Meter (m): The base unit of length.
• Decimeter (dm): 1 dm = 0.1 m
• Centimeter (cm): 1 cm = 0.01 m (10 centimeters make a decimeter)
• Millimeter (mm): 1 mm = 0.001 m (100 millimeters make a decimeter)

The relationship can be visualized as:

$$1 \text{ m} = 10 \text{ dm} = 100 \text{ cm} = 1000 \text{ mm}$$

Common Uses and Examples

While not as commonly used as centimeters or meters, decimeters can be found in specific contexts:

• Education: Sometimes used in elementary science and math to teach the metric system.
• Technical Drawings: Occasionally used in technical drawings or specifications where more precision than a meter but less than a centimeter is needed.
• DIY projects: In scenarios that involve very small spaces, you may find that the decimeter is the perfect unit of measure.
• Volume: A cubic decimeter ($dm^3$) is equivalent to a liter, a common unit for measuring liquid volume.

Historical Context and Notable Associations

While no specific law or famous person is uniquely associated with the decimeter, its existence is tied to the development and adoption of the metric system during the French Revolution. The metric system was designed to be a universal, rational system of measurement based on powers of ten.

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.