What Are Survey Errors and How They Are Rectified in the Course of Maintenance

The following are the four types of survey errors.

Table of Contents

1. Measurement errors:

If the same line was measured twice the result would hardly ever be the same and this difference was due to the inevitable practical error which crept despite all our care. As measurement progresses more or less tension in the chain will inevitably occur due to improper arrows planted or manipulation when measuring up and down with elevated ridges.

If the above allowances exceed it may be considered a survey error.

2. Plotting errors:

The difference in area is 5% due to errors in plotting anything beyond this allowance is considered a plotting error.

3. Area errors:

Case-1: The area of the Survey field or any subdivision the difference between the actual area and the registered area is below 5%, therefore, the registered area may be noted and no changes are needed.

Case-2: The total area of the Survey field should not be more than 5% of the actual area but the actual subdivision area may any one of them exceeds the registered area.

Case-3:The area of Survey field, the difference between actual area and registered area is above 5% therefore the actual area may be noted.

4. Traverse Errors:

Error, in the case of village circuits, should not exceed one minute for 5 angles. In the case of Khandam circuits should not exceed one minute for 2 angles. As well as in measurements, error up to 1 link allowance in village circuits for 10 chains and in Khandam circuits, 2 links.

How it is rectified in the course of maintenance?

A discrepancy between the recorded measurement and a measurement taken on the ground should not be treated as an error unless it exceeds 5 links up to a distance of 5 chains and not more than one link per chain for a distance of above 5 chains, subject to the maximum to 10 links in wet and 20 links in drylands. If the difference exceeds this limit, the line will be remeasured and the village copy of F.M.B. corrected, provided that the area of the Revenue field is not altered by more than 5%. All corrections made in the F.M.B. should be initialled by the Surveyor or Deputy Inspector of Survey and the date of correction entered in the margin.

The correction of an error in the calculation of area which involves an alteration in the area of a Revenue field by more than 5% should be dealt with in the manner prescribed in Para 7 of BSO 34-B.

The difference of more than 5% between the actual area computed and the registered area of a Revenue field will be treated as an error in area. The procedure for correcting the Survey Errors involving alternation in alteration is explained below:

The Mandal Surveyor will after completing the re-measurement, prepare and submit to the Mandal Revenue Officer (Tahsildar) revised maps in duplicate and also draft notices in the prescribed form (Appendix XIV) calling for objections within 15 days from the date of receipt of such notice.
The M.R.O. will serve the notices on the parties concerned, note on the duplicate copy the date on which any objections were heard by him, and an abstract of his orders, and forward all the connected records to the Deputy Inspector or Asst. Director Survey & Land Records.
The Divisional Dy. Inspector /Asst.Director should scrutinize the maps and records, prepare a memorandum of alterations in the prescribed form and submit the file to the Collector.
After approval by the Collector the case should be entered in the “Register of Survey Errors corrected” which will be maintained by the Dy. Inspector/ Asst. Director. The records should then be returned to the M.R.O. who will have the revised field maps inserted in the Village F.M.B. and Taluk copy of the F.M.B. and corrections made in the permanent “A” Register.
The file should then be given disposal No. and recorded in the Taluk Office after intimation to the Assistant Director, of the date of insertion of the copy of the field map in the Taluk F.M.B.
The correction of an error in the calculation of area which involves an alternation in the area of a Revenue field should be dealt with in the above manner with the exception that revised maps need not be prepared.