Linear Measurement Methods

The word Linear is derived from the Latin word Linearis. 'Created by lines is the factual meaning of the word Liner'. The mathematical meaning of the word Linear is something which is in a straight line. In short the measurement of length is generally known as linear measurement. Measuring the horizontal distance between two points on the surface of the earth is one of the most fundamental surveying operations. Usually, there are two basic methods used: direct and indirect. In Direct linear measurements horizontal distances are calculated with the aid of a tape or chain or with an electronic distance-measuring instrument. In indirect methods, to determine the exact measurements the transit and stadia or theodolite and stadia are used.  

 Direct Linear measurements

To calculate linear   measurements   for construction surveys, triangulation base lines, and traverse distances, a common method known as chaining is used. In modern world  electronic  distance-measuring  system  is now  integrated  in various   surveying practices, like traverse  and  triangulation network. Accurate distances are directly measured in a straight line in traverse measurement with minimum instruments.  In triangulation, base line  measurements  that  are  precise are calculated and these details are enough to maintain  the  accuracy  of  the  survey. Triangulation is a surveying technique in which a region is divided into a series of triangular elements .division of a particular region is based on a line of known length and this helps to obtain accurate measurements of the distances.

Importance of Linear Measurement

EDM instruments are used in all linear measurements. But in some lower order work, such as close staking out and building measurements it is difficult to use EDM instruments. In linear measurement method a steel tape is used to obtain accurate and perfect measurement of distances. It is believed by many surveyors that that third order precision gained by linear measurement is a natural result of taping a distance. If correct procedures are followed taped measurements can use linear accuracy to obtain exact measurements. Standardization of tape, application of temperature correction, application of correct horizontal & vertical alignment of tape, and careful plumbing measures are some of the correct procedures of tape measurement.

Units of Linear Measurements

Linear measurement is a measurement method in surveying used to express distances and it can indicate the differences in their altitudes. Foot and Meter are the standard units of linear dimension. Tenths, hundredths, and thousandths for measurements of these standard units are used in surveying techniques. Foot is prolonged into an edict or to a naval mile and the meter into a kilometer when longer distances are calculated.

Questions:

• What are the methods of linear measurements?
• Explain the importance of linear measurement?