An FMB sketch (Field Measurement Book sketch) is the official survey drawing of a single survey number, showing its shape, subdivisions, boundary measurements and the neighbouring survey numbers. In Tamil Nadu you can download it free from the Revenue Department’s eServices portal. For a land buyer, it is the document that tells you whether the plot you are standing on is actually the plot described in the sale deed.
Key takeaways
- The FMB shows the shape, subdivisions and measured sides of a survey number, plus adjoining survey numbers.
- It is maintained by the Survey and Land Records department and can be downloaded free online.
- Compare the FMB with the sale deed schedule, the patta and the physical boundaries on site.
- If the FMB does not match the ground, get a licensed or government surveyor to measure before you pay.
What the FMB is, and where it comes from
When Tamil Nadu’s lands were surveyed and resurveyed, each village was divided into survey numbers, and each survey number was drawn to scale in the Field Measurement Book. Whenever a survey number is split, for example when a farm is sold in parts or converted into a layout, the surveyor adds the new subdivision lines to the FMB. The records are maintained by the Survey and Land Records department at taluk level, and have been digitised so that computer-generated extracts can be issued instead of hand-copied sketches.
The FMB is a technical survey document, not a title document. It tells you where a piece of land is and how big it is, while the patta tells you whose name it is recorded in, and the sale deed and EC tell you how it changed hands.
How to download an FMB sketch online
- Open eservices.tn.gov.in, the Tamil Nadu land records eServices portal.
- Choose the option to view the Field Measurement Sketch (FMB / FMS).
- Select district, taluk and village, and enter the survey number.
- Download the PDF. Copies of the Field Measurement Sketch are provided free of cost on this e-service.
The Tamil Nilam Geo-Info mobile app from the State’s e-governance agency also shows survey boundaries on a map, which is handy on a site visit. For urban lands in town survey areas, the equivalent records are kept in the town survey system, and some sketches may need to be obtained from the taluk or town survey office.
How to read an FMB sketch
A first look at an FMB can be confusing: a polygon full of lines and small numbers. Break it down piece by piece.
| What you see | What it means |
|---|---|
| Large number in the centre | The survey number the sketch is for |
| Smaller numbers or letters inside divided areas | Subdivision numbers, for example 45/1, 45/2A |
| Numbers along each side | Measured lengths of the boundary lines between points |
| Numbers outside the boundary | Adjoining survey numbers on each side |
| Small circles or marks at corners | Survey stones or boundary marks fixed in the field |
| Dotted or dashed lines | Features such as cart tracks, channels or internal lines, depending on the sketch legend |
| Scale and north arrow | Orientation of the land and the scale used for drawing |
A note on units
Older FMBs may record lengths in chains and links, while resurveyed records generally use metres. Extents on the patta are usually given in hectares and ares. Coimbatore buyers talk in cents and acres, so convert carefully: 1 acre is about 0.4047 hectares, and 1 cent is one hundredth of an acre, about 40.47 square metres. When in doubt, ask the surveyor to confirm the unit used on your sketch.
Five checks to make with the FMB
- Survey and subdivision numbers match. The numbers in the sale deed schedule, the patta and the FMB must be identical.
- Extent matches. The area worked out from the FMB should be consistent with the extent in the patta and the deed.
- Shape and boundaries match the site. Walk the boundary. Road frontage, the shape of the land and the neighbours should match the sketch.
- Access is real. If the FMB shows no road or pathway next to your subdivision, ask how you will legally reach the plot.
- Neighbouring features. Check whether an adjoining survey number is a water body, channel or other poramboke land. Encroachment risk is higher next to these; see our guide to poramboke land.
When the FMB and the ground do not match
Mismatches are common in older villages and in fast-growing suburbs around Coimbatore, such as the belts along Sathy Road and Pollachi Road where farmland has been converted in stages. Sometimes the subdivision was never recorded, sometimes fences have moved over decades, and sometimes the seller is simply showing the wrong piece of land. Do not rely on a broker’s pointing finger.
Ask for a physical survey. You can apply to the taluk survey office (through e-Sevai or the Tamil Nilam citizen portal) for measurement and boundary demarcation, or hire a licensed surveyor for a private check. If subdivisions need to be created, that goes through the patta transfer process with subdivision. Our guide on land survey and boundary disputes covers what to do next.
FMB for layout plots and apartments
For a DTCP or LPA approved layout, you will also have the approved layout plan showing plot numbers, roads and open space reservation. The FMB should reflect the survey number of the parent land, and ideally the individual plot subdivisions. For an apartment, the FMB of the land underneath still matters, because your undivided share of land sits on that survey number. Check it alongside the approvals covered in our DTCP vs RERA guide.
Frequently asked questions
Is the FMB sketch free in Tamil Nadu?
Yes. The eServices portal states that copies of the Field Measurement Sketch can be downloaded free of cost.
Is an FMB sketch proof of ownership?
No. It is a survey record of location, shape and measurements. Ownership is shown by the title deeds, supported by the patta and EC.
Why is my subdivision not on the FMB?
The land may have been sold in parts without a formal subdivision. The buyer usually applies for patta transfer involving subdivision, after which the surveyor updates the FMB.
Can I use the FMB to fix a boundary dispute?
It is the starting point. For a dispute, apply for an official survey and boundary demarcation through the taluk survey office rather than relying on a printout alone.
This article is general information as of September 2026, not legal, tax or financial advice. Rules and rates change; confirm with a qualified advocate, chartered accountant or the relevant department before you act.
References
- Tamil Nadu eServices: land records and FMB sketch
- Nagapattinam District: Survey and Settlement functions (FMB, subdivision, demarcation)
- Tamil Nadu Survey and Boundaries Act, 1923 (Indian Kanoon)
Want to be sure the plot matches the papers?
Our Coimbatore team can help you line up the FMB, patta and sale deed, and arrange a survey before you commit.
