How do you define datum?

How do you define datum?

A datum is a plane, a straight line, or a point that is used as a reference when processing a material or measuring the dimensions of a target.

What is an example of datum?

An example of a datum is a new scientific discovery used to reach a conclusion about the common cold. An example of a datum is the assumed altitude of a specific piece of land used as the basis in calculating the altitude of the top of a mountain on the land.

What is a datum used for?

Geodesists and surveyors use datums to create starting or reference points for floodplain maps, property boundaries, construction surveys, levee design, or other work requiring accurate coordinates that are consistent with one another. There are two main datums in the United States.

What is datum of the earth?

A geodetic datum is a tool used to define the shape and size of the earth, as well as the reference point for the various coordinate systems used in mapping the earth. Throughout time, hundreds of different datums have been used – each one changing with the earth views of the times.

What is datum in aviation?

Datum (reference datum)—an imaginary vertical plane or line from which all measurements of arm are taken. The datum is established by the manufacturer. Once the datum has been selected, all moment arms and the location of CG range are measured from this point.

What do you mean by datum surface?

In engineering and drafting, a datum is a reference point, surface, or axis on an object against which measurements are made.

What are map GPS datums?

A datum is a model of the earth that is used in mapping. The datum consists of a series of numbers that define the shape and size of the ellipsoid and it’s orientation in space. Another example, familiar to GPS users, is the WGS-84 datum. WGS-84 is an example of a datum that is used globally.

Why are there different datums?

Because there are different ways to fit the mathematical model to the surface of the Earth, there are many different datums. Also, in the modern digital era, techniques have vastly improved and many modern datum are very similar to each other.

How do I find my datum?

On a USGS topographic map the datum information is in the fine print at the bottom left of the map. The datum will always be NAD 27. There may be information on how many meters to shift a position to convert it to NAD 83. Think of this as the error that will be introduced if you leave your GPS unit set to WGS 84.

What datum is Google Maps?

Google Maps and Microsoft Virtual Earth use a Mercator projection based on the World Geodetic System (WGS) 1984 geographic coordinate system (datum).

Where is the datum on an aircraft?

The horizontal reference datum is an imaginary vertical plane or point, placed along the longitudinal axis of the aircraft, from which all horizontal distances are measured for weight and balance purposes. There is no fixed rule for its location, and it may be located forward of the nose of the aircraft.