Geography & History Notes | KCSE, NECTA, ZIMSEC & GCSE

  An error is a mistake or shortcoming that happens during the survey process leading to wrong measurements. It is sometimes called discrepancies . The following are the type of errors or discrepancies in chain surveying. Sources of Errors in Chain Survey and Their Correction The errors can be divided into three groups: Cumulative (systematic) errors Compensating (accidental) errors Gross Errors Cumulative Errors: Cumulative errors are said to be systematic errors as they are one-directional hence keep on accumulating as the survey progresses. If not checked they have serious implications to the accuracy of the survey. Errors in this class include incorrect length of the tape, page of the tape or the tape not being in line. Since the sources of these errors are known, they can be eliminated. They can either be positive or negative errors. While positive errors shortens the measurement (e.g. where the tape length is shorter than what it should be) while negative errors elongates th...

  A chain survey is a simple land survey that deals with measuring and recording a series of linear distances on the ground by using a chain or a tape measure. The chain survey is the simplest method of surveying . In this survey, only measurements are taken in the field, and the rest work, such as plotting calculation, etc. are done in the office. This is most suitable adapted to small plane areas with very few details. If carefully done, it gives quite accurate results. The necessary requirements for field work are chain, tape, ranging rod, arrows, and sometimes cross-staff. The following are disadvantages of simple chain survey: A simple chain survey can not be conducted in built-up areas and large areas. A simple chain survey is subject to several chances of errors of accumulation which may be caused by the problem of the chain. The chain linkage may fail to stretch up properly and result in inaccurate data . Also clogging of the chain may read to an error in reading. It is ti...

  Chain surveying , It is a method of Surveying in which no angles are measured but the only linear measurement is taken in the field by using a chain or tape measure. It measures a series of straight lines on the ground with a chain or tape measure and all fixed points relative to the line of traverse either by right angles (offsets) or tie lines.   Equipment used in chain surveying. Chain  The chain is made up of steel wire which is divided into links and togs (rings) to facilitate folding.  It is sometimes used as a unit of measurement It has brass handles at both ends for easy handling. The link is 0.2m or 200mm in diameter. The length is 20m or 30m. ii.Tape Steel tape Linear tape A tape is made from fiberglass or a steel strip and is 10m, 20m or 30m in length graduated in 10mm divisions and numbered at each 100mm (10) divisions It is used for measuring short distances iii. Ranging poles are made up of wood or light metal and measure about 2m long at t...

  A chain survey is a simple land survey that deals with measuring and recording a series of linear distances on the ground by using a chain or a tape measure. The chain survey is the simplest method of surveying. In this survey, only measurements are taken in the field, and the rest work, such as plotting calculation, etc. are done in the office. This is most suitable adapted to small plane areas with very few details. If carefully done, it gives quite accurate results. The necessary requirements for field work are chain, tape, ranging rod, arrows, and some time cross-staff. The following are advantages of chain survey: Chain survey is simplest and commonest method used in surveying exercises The equipment used to conduct chain survey are simple to use, The equipment used in chain survey can easily be replaced. For example, measuring rods can be replaced with measuring tape.  This method does not involve complicated mathematical calculations. I know this is the relief to thos...