FMB Sketch Explained: Checking Plot Boundaries in Tamil Nadu

Why this matters for a first plot

Many first-time buyers near the Karnataka–Tamil Nadu border look at plots before flats. A plot feels simple: land is land. But the land you are shown and the land in the record can differ by a few feet, and a few feet can decide whether your house plan fits.

Fence, wall and boundary

A fence is put up by a person. A compound wall is built by a person. A boundary is fixed by the survey record. Buy the boundary, not the wall.

What the FMB shows

The Field Measurement Book sketch is a drawing of one survey field. It shows the field's outline, the length of each side, and the survey numbers around it. It is the bridge between the words in your documents and the soil under your feet.

How one field becomes many plots

When a field is divided, each part gets a sub-division number. So survey number 123 might become 123/1, 123/2A and 123/2B. Check that the same sub-division number appears in the sale deed, the patta and the FMB. A mismatch here is the most common paper problem.

Getting a measurement done

You can apply at the taluk office for the land to be measured. A surveyor visits and records the result. Ask for a copy of what is recorded. If you are buying in a layout, ask the developer whether the layout's sub-divisions have already been measured and recorded.

Reading the sketch on the ground

• Find one fixed point, such as a road corner or a survey stone.
• Walk each side and compare with the lengths on the sketch.
• Check that neighbouring survey numbers sit where the sketch says.
• Note anything odd: a wall at an angle, a path through the plot, a channel.

Stones and markers

Survey stones or corner markers are placed at field corners. Photograph each with your phone so the date and location are saved. They become useful if a dispute ever arises.

Questions for a layout developer

1. Which survey and sub-division numbers make up my plot?
2. Can you share the FMB for those numbers?
3. Has the layout been sub-divided in the revenue records?
4. Has a patta been issued for my plot, or when will it be?

Land units you will meet in Tamil Nadu

Tamil Nadu records often use cents and hectares, and sellers often talk in grounds. Keep these conversions handy:

• 1 acre = 100 cents = 43,560 sq ft.
• 1 cent = 435.6 sq ft.
• 1 ground = 2,400 sq ft (a common unit around Chennai).
• 1 hectare = about 2.471 acres.

Worked example: checking a plot's area

Illustrative figures only. A seller offers a plot "of 5 cents" and shows you a rectangle on the ground, 40 ft by 54 ft.

• Area on the ground: 40 × 54 = 2,160 sq ft.
• Area of 5 cents: 5 × 435.6 = 2,178 sq ft.
• Gap: 2,178 − 2,160 = 18 sq ft.

A gap of 18 sq ft is less than 1% and could come from rounding or measuring by tape. Now imagine the ground measures 36 ft by 54 ft, which is 1,944 sq ft. The gap is 234 sq ft, more than 10%. That is not rounding. Something is wrong, and you should find out what before you pay.

Step by step: verify a plot's boundary

1. Collect the papers. Sale deed, patta, the FMB sketch for the survey field, and the approved layout plan if it is in a layout.
2. Match the numbers. Survey number and sub-division should be the same on all of them.
3. Match the area. Convert everything into square feet using the units above, and compare.
4. Find a fixed point on site. A survey stone, a road corner or a corner of the layout.
5. Measure the sides. Use a long tape. Write down each side.
6. Check the neighbours. The survey numbers on each side should match the FMB.
7. If in doubt, ask for an official measurement through the taluk office, and wait for the result before paying.
8. Ask your lawyer for a written opinion that covers the title and the boundary.

Warning signs on site

• A footpath or cart track crosses the plot. It may be a recorded right of way.
• A channel, pond edge or stream bed runs along or through it. Water bodies are often protected.
• A neighbour's wall leans into the plot, or yours would lean into theirs.
• The plot's shape on site is clearly different from the sketch, such as a rectangle on paper and a wedge on the ground.
• Survey stones are missing, moved or newly placed with no record.

Common mistakes first-time plot buyers make

• Measuring only the front. The rear width can differ, and that changes the area.
• Using the seller's measurement. Measure yourself, or pay a licensed surveyor.
• Ignoring sub-division numbers. 123/2A and 123/2B are different pieces of land.
• Confusing patta with title. A patta records who holds the land for revenue purposes. Your lawyer still needs to check the chain of sale deeds.
• Buying across the border without checking the state. A plot a few kilometres from Attibele may be in Tamil Nadu, with different records, portals and offices from Karnataka.

What to keep in your file

Once you are satisfied, keep together: a copy of the FMB, the patta, the sale deed, your own measurements with dates, and phone photos of each corner stone. If a dispute ever comes up, a neat file with dated evidence is your best friend.

A quick checklist before you sign

• FMB sketch for the right survey field, with the sub-division shown.
• Patta in the seller's name, for the same sub-division.
• Sale deed schedule matching both, including boundaries on all four sides.
• Area on paper and area on the ground within a small, explainable gap.
• Corner stones found and photographed.
• No path, channel or water body inside the plot.
• Layout approval seen, if the plot is in a layout.
• Your own lawyer's written opinion.

Tick every line before the final payment. A day spent on these checks is cheap compared with a boundary dispute that can take years to settle.

Questions to ask before the final payment

1. Is the patta in the seller's name for this exact sub-division?
2. When was the land last measured officially, and can I see the record?
3. Are all four boundaries in the sale deed the same as on the FMB?
4. Is there any path, channel or easement recorded across the plot?
5. Who will apply for the patta transfer after registration, and how long will it take?

Ask these in writing and keep the answers. A seller who answers clearly, with papers, is making your decision easier. A seller who avoids them is telling you something too, and it is worth listening.

Weighing a plot against a flat? Our first-home guide sets the two side by side.