Diagonal and Offset System of Survey (D and O System)

This is the latest survey method in use. In the land survey, the main processes are location, demarcation, measurement, mapping, calculating the area of the fields, preparation of field registers or land registers to carry out settlement work. The whole activity has to be carried out through various processes/work.

I)A-WORK (BOUNDARY DEMARCATION)
II)B-WORK (TRAVERSE SURVEY)
III)C-WORK (TRAVERSE COMPUTATION)
IV)D-WORK (TRAVERSE PLOTTING)
V)E-WORK (FIELD DEMARCATION)
VI)F-WORK (FIELD MEASUREMENT)
VII)G-WORK (PREPARATION OF VILLAGE MAP)
VIII)H-WORK (FINISHING VILLAGE MAP AND AREA CALCULATION)

I). A-WORK (BOUNDARY DEMARCATION):

The main principle of large operations of the survey is whole to part. Thus the village boundary is first demarcated.

The following are the operations carried out in A-work.

(I). Village boundary demarcation:

Determining the boundaries of a village in the presence of the village people, village heads, and villagers on either side, starting from the points of the trijunctions where more 3 or more villages meet. Stones are laid for theodolite work at the trijunctions stations of the village. The point Where two villages meet is called the Bi-junction and if the three villages meet is called Trijunction. A-work surveyor roams around the village boundary and places A-class stones at Tri-junctions and Pointers and at Bi-junctions, B-class stones are planted. The distance between stone to stone should be as far as possible i.e.,10-40 metric chains, without any obstructions in between them.

(II). Line Clearance:

During the demarketing of village boundaries, any obstruction between stations such as mounds, trees, bushes, etc., may be removed or cleaned with the help of the village revenue assistant or with the help of villagers.

(III). Formation of Khandams:

On completion of the demarcation of village boundaries, the village’s entire circuit should be divided into Khandams. While forming Khandams, the extent of Khandam may be in the range of 100 to 200 acres for wetlands, 200 to 300 acres for drylands, and 150 to 250 acres for the combination of the dry and wetlands.
Khandam boundaries should be chosen in such a way that avoids the line clearance but must follow existing and natural boundaries.

(IV). Minor Circuit Fields:

With the help of Chain and cross-staff, the immeasurable Grama Kantams, Mounds, ponds of land beyond 50 acres, within the area of 100 acres also need to be identified separately, these are called minor circuit fields.
Although with the help of Chain and cross-staff, if the land is measurable of more than 50 acres of land is owned by a single landlord, it is also measured as MC field.

(V). Topo Detail:

The primary object of the survey is the preparation of the plan. The plan should exhibit the topography of the land. topography means detailed delineation or description of physical features of a place such as hills, valleys, roads, railways, etc.

(II). B-WORK (TRAVERSE SURVEY):

After doing the A-work, the surveyor records the details he has prepared in the survey office. Based on that another surveyor will perform the B-WORK. The village boundary, the Khandam boundary, and the MC field. etc., are angled with the help of a theodolite machine and measure the distance between stations separately with a 20 meters and 30 meters chain. This is called as Traverse survey.

(III). C-WORK (TRAVERSE COMPUTATION):

The details provided by the B-work surveyor ( i.e., angles and dimensions) calculate the area of the village, Khandam, and MC field in the office. This is called Traverse Computation.

(IV). D-WORK (TRAVERSE PLOTTING):

Based on the above details, the framework will be plotted and a skeleton sketch may be prepared. The maps of MC fields, Khandams, Topo details, and village boundary shall be prepared with proper scale, this is called Traverse plotting.

(V). E-WORK (FIELD DEMARCATION):

• In such a way that takes realistic measurements before starting the Survey holdings (field) to be surveyed should first be demarcated and their rough sketch should be made to guide the Surveyor. Survey fields are selected during the location work.
• As well as with the specifications of revenue account and a land register is also prepared with details of each field of the name of a person enjoying, its classification, nature, etc…
• It should be noted that revenue field and survey fields are different, therefore some enjoyments are clubbed together to form the survey field.
• The Deputy surveyor will be furnished with the boundary demarcation sketch of the village. He should demarcate the fields commencing with the first Khandam of the village and be guided by the following rules.
• A revenue field, i.e., a field registered in the revenue accounts may be either occupied or unoccupied. If occupied, it is a distinct piece of land of one description of soil and held on one tenure by one man or jointly by more. If unoccupied, it is either Poramboke or waste assessed or unassessed. Occupied revenue fields always form distinct items in a patta. A paimash field may be a revenue field or it may contain two-or-more revenue fields.
• Revenue fields should be clubbed to form survey fields up to a maximum of 2 Hectares in wetland and 4 Hectares in dry land. In a survey field so formed, each revenue field will form a separate subdivision. If two or more previously existing revenue fields (still separately registered) which are contiguously situated have passed into the enjoyment of a single individual or the enjoyment of several persons who hold and enjoy them jointly and in common and are of the same description of soil and tenure they should be formed into a single subdivision of the survey field.

• Formation of survey fields:

1. Revenue fields should be clubbed to form survey fields up to a maximum extent of 2 hectares (5 acres) in wetlands and 4 hectares (10 acres) in drylands.
2. No survey field thus formed should contain more than 20 subdivisions unless its area is below 2 acres in wetlands and 4 acres in drylands when no limit is placed on a number of subdivisions.
3. All roads, cart tracks, and channels are shown as Poramboke in revenue accounts, and those which are included in the ryotwari holdings and which exceeds 20 links in width Should be demarcated as separate survey field. If the width is between 50-20 links, they should be formed as a subdivision in the survey field. if the width is less than 20 links it should be shown as topo detail. If the width is greater than 50 links and the length of 10 chains, it should be treated as a long narrow field.
4. Equalization of Bends:- Small bends between the fields can be straightened in the presence of the farmers on either side up to 10 links in wetlands and 20 links in dry land. This cannot be done when there is a wetland on one side and drylands on the other side or government land or vice versa, valuable trees or the buildings on the fields. Equalization of bends cannot be done when the Pattadars disagree.

• No existing revenue fields however large, are to be sub-divided except by special order of the Asst. Director.
• Large waste block fit for cultivation should be divided into 4 hectares’ fields, following where convenient the limits of Sivayi Jama cultivation, care being taken to secure regular field boundaries.
• Where a road runs through Government waste, its limits should be marked at a maximum distance of one chain on each side of the centerline of the roadway.
• Before marking out the boundaries of railway lands, the local railway authorities must be communicated with, asked for copies of land plans, and written permission obtained to enter on their premises when necessary.
• The holdings in each survey field are identified as sub-divisions and a location sketch is made. Survey field boundaries are marked as continuous lines and sub-divisions are marked as broken lines. The survey fields are marked with numbers respectively. The assignment of these numbers starts from the North-West corner and ends with the South-East corner. The same is given for each survey number (sub-divisions) until the last Khandam in the village continues the same line until the last survey number. It also starts in North-West and ends in the South-East. This is called the “Rough Location Sketch”.

The symbols to be used in the sketch for the different kinds of stones are

The surveyor should sign the sketch in the lower right-hand corner and enter the dates of commencement and completion of the Khandam. No more writing is allowed.

(VI). F-WORK (FIELD MEASUREMENT):

• The measurement of no survey field should begin until all stones have been fixed on its boundaries.
• The Boundaries of all fields are demarcated under the rules in the above E-Work, in this work we take field measurements of each field survey field wise is called F-Work.
• In this we first take the Field measurements of subdivisions of the Survey field, then next we will find outfield Tri-junctions and draw diagonal lines ‘G’ lines between them. The diagonal line is like the backbone of the survey field. This is just speculation. This is also known as the Guess line. It is determined between the two fields. The diagram below explains how the measurements should be made and recorded:
• We have to follow a certain principle while making these diagonals

1. i.e., Number of junctions-2 (n-2)
2. For example: suppose we have a field that contains 5 junctions say A, B, C, D, E. Then we have to form 3 diagonals(n-2=5-2=3) based on a formula. the distance between the junctions should be short. Junctions offsets should be taken from Diagonal lines. If there are small bends above the next field line, add common ‘G’ lines from junction to junction and take offset from it. The offset of the bend should be taken on the line which is closest to the ‘G’ line of the survey field or subdivision that we have. Let us set aside all the measurements made on the earth in the form of a Ladder. Only ‘G’ lines and ‘F’ lines should be drawn in the sketch. We should not take the length of offsets to be more than 5 chains under any circumstances.

(VI). G-WORK (PREPARATION OF VILLAGE MAP):

• All the survey fields that we have measured in the ‘F’ work, are plotted in the traverse skeleton which is made in the ‘Demarcation’ process.
• Where different measurements are recorded for the same line in rejoining fields, and the difference is not more than three links in distances of five chains and under, not more than one link per chain in distances of over five and under ten chains, and not more than ten links in distances of ten chains and over, that measurements should be retained which is nearer the theoretical length of the line as calculated from the recorded diagonal and offset distances the other measurement corrected.
• The plotting of the fields in the village map should begin after the traverse plotting of the boundary and Khandam circuits, and the laying out of the points offset from the village and Khandam boundary and cross Purtal lines have been completed. In special cases the Asst. Director may permit field plotting of a portion of a village being proceeded with, while the traverses or Purtals not affecting that portion remain un plotted.

(VI). H-WORK (FINISHING VILLAGE MAP AND AREA CALCULATION):

The village map prepared in the ‘G’ process will be neatly prepared and the area of the Skeletons and Survey fields will be calculated. The differences in the two areas are examined and We have an allowance of 1%. That is, if there is a difference of 1%, it can be accepted.

• The map and all other records should be finally examined by the Senior computer, senior draftsman, and office manager. The final examination report and all other records should be signed by the Asst. Director.
• After completion of mapping, a third and fair copy of the field measurement book should be prepared in the Survey office.
• Appeals from the orders in these notices and from those passed under section 10 (2) are to be filed within three months of the date of the service of the notice, but the period of appeals time shall not include the time taken to secure a copy of the decision and map.
• The appellate authority can admit an appeal after the lapse of appeal time provided he is satisfied that an applicant had good and sufficient cause for not preferring the appeal within the time allowed.
• On completion of the survey in accordance with the orders passed under sections 9, 10, or 11 of the Act, the Asst. Director shall publish the notification, required by section 13 of the Act.
• The initial survey records of a village will consist of the following:

1. Boundary demarcation sketch
2. Traverse field books
3. Traverse sheets
4. Field demarcation sketches
5. Field register (in duplicate in the case of estate villages not followed by a record of rights.”)
6. Field measurement book (in triplicate)
7. Inspection reports
8. Village map
9. Area list (rough and fair)
10. Final examination report