Error in chain survey

 Error in chain surveying

There are various sources of errors in chain surveying. Errors can be cumulative or compensating. Cumulative errors are those tens in addition as the measurement continues. Compensating errors are those which tend to become positive sometimes and negative at another time. The following errors in chaining should be avoided.

• Incorrect length of chain
• Incorrect training ranging
• Loose chain
• Temperature Change
• Variation In pull
• Error in slope Measurements
• Personal mistakes

Incorrect length of chain

The actual length of the chain used for measurement may be different from the designated length. The chain may be shorter or longer than the designated length.

So that, the length of the chain should check before the start of the survey and correct before chaining.

Loose chain

If the chain is not pulling correctly while chaining the measured length will always be more. So that chain should be pulled correctly during chaining.

Incorrect Ranging

If the chain placed out of the line while measuring alone, the measured length will always be more. So that, ranging should be correct before taking the measurement.

Temperature change

If a chain or tape standardize at some temperature and the temperature during the measurement is much different. There will be errors in the gaining due to changes in the length of the chain or tape. This type of error should compensate by correcting the length measured.

Variation in pull

If the pull applied during the chain is different from the standard pull, the length of the tape will change. So that during the chaining pull shot apply correctly.

Errors in slope measurements

While measuring alone a slope using the stepping method, the chain may be straight during measurement which results in an error. So, the chain should keep straight while measuring along the sloping ground.

Advantages of Chain Survey

• The equipment used to conduct chain survey is simple to use.
• Chain survey is the simplest and commonest method used in surveying exercises.
• The equipment used in chain survey can easily be replaced.

Disadvantages of Chain survey

• A simple chain survey cannot be conducted in built-up areas.
• It is time-consuming
• Chain survey becomes a more complicated method when there are raised points in between areas to be surveyed.