Survey Number History API: UDR and town survey renumbering

Example

Request

curl -X POST https://verified.realestate/api/v1/tools/survey_history \
  -H "Authorization: Bearer $LANDLENS_KEY" \
  -H "Content-Type: application/json" \
  -d '{"direction":"old_to_current","district_code":"35","taluk_code":"13","town_code":"005","old_survey_number":"59/1"}'

Responsereal answer

{
  "ok": true,
  "status": "ok",
  "data": {
    "found": true,
    "direction": "old_to_current",
    "old_survey_number": "59/1",
    "register": "Town survey register (old-number field)",
    "matches": [
      {
        "ward": "002",
        "block": "0056",
        "survey": "32",
        "old_number_as_written": "59/1",
        "owner": "",
        "owner_en": ""
      },
      {
        "ward": "002",
        "block": "0056",
        "survey": "33",
        "old_number_as_written": "59/1",
        "owner": "",
        "owner_en": ""
      }
    ],
    "match_count": 5,
    "note": "Current town survey parcels whose register entry names 59/1 as the number they replaced. A part marker on the old number means the old field was split. A parcel listed here is one the register derives from that number; which one a deed conveys is settled by its schedule and the FMB, not by this list.",
    "what_udr_means": "UDR is the Updating Registry scheme of 1 June 1979 to about 1987, which re-measured every ryotwari village outside Madras, the Nilgiris and Kanyakumari, effected pending sub-divisions and issued fresh A-registers and FMBs; town survey later replaced revenue survey numbers with block-scoped T.S. numbers in the towns. The register keeps the earlier number against each parcel, which is what this answer reads."
  },
  "credits_charged": 1
}

A real answer from the API (22 Oct 2026). Five parcels matched; the three in private hands are left out here, and match_count is shown as returned.

What it returns

One call, a list of matches. found is false (status not_found, nothing charged) when no parcel matches.

Field	What it holds
`matches[] (old_to_current)`	Each current parcel: survey, old_number_as_written, owner_en. Town land adds ward, block and the owner in Tamil; village land adds patta_no, land_type and extent.
`matches[] (current_to_old)`	Each parcel under the current number: survey, old_survey_number (or null), kind (what sort of earlier number it is), owner_en, and for village land patta_no and land_type, for town land ward and block.
`match_count`	How many parcels matched (old_to_current).
`register`	Which register answered: the town survey register or the revenue A-register.
`note`	What the matches mean, in plain words.
`what_udr_means`	A short explanation of the Updating Registry scheme and town survey renumbering, for the reader.

Ways to call it

Choose a direction. Both need the district and taluk codes, and a village code (village land) or a town code (town survey land).

Old to current

An old number from a deed in, the current parcels out.

{"direction": "old_to_current","district_code": "35","taluk_code": "13","town_code": "005","old_survey_number": "59/1"}

Current to old

A current survey number in, its earlier number out.

{"direction": "current_to_old","district_code": "35","taluk_code": "13","town_code": "005","survey_number": "66","sub_division": "1"}

Inputs

The JSON body of the POST is the arguments. direction, district_code and taluk_code are required, with a village or town code. resolve_revenue_codes gives them at no charge.

Argument	Type	What to send
`direction`required	string: old_to_current, current_to_old	Which way to look
`district_code`required	string	Revenue district code, e.g. 35
`taluk_code`required	string	Taluk code, e.g. 13
`village_code`	string	The village code, for village land. Send this or town_code.
`town_code`	string	The town code, for town survey land.
`old_survey_number`	string	For old_to_current: the old number as the deed writes it, e.g. 186/4 or R.S.No 59/1
`survey_number`	string	For current_to_old: the current survey number, e.g. 45
`sub_division`	string	For current_to_old: the sub-division, e.g. 4 or 2A1
`register`	string: rural, urban	Optional: "urban" says village_code is really a town code.

Code

Set LANDLENS_KEY to your key. In an AI app, connect https://verified.realestate/mcp once and ask in plain words instead. In Postman, download this API's collection, import it (File, Import) and set apiKey.

curl -X POST https://verified.realestate/api/v1/tools/survey_history \
  -H "Authorization: Bearer $LANDLENS_KEY" \
  -H "Content-Type: application/json" \
  -d '{"direction":"old_to_current","district_code":"35","taluk_code":"13","town_code":"005","old_survey_number":"59/1"}'

import os, requests

r = requests.post(
    "https://verified.realestate/api/v1/tools/survey_history",
    headers={"Authorization": f"Bearer {os.environ['LANDLENS_KEY']}"},
    json={
        "direction": "old_to_current",
        "district_code": "35",
        "taluk_code": "13",
        "town_code": "005",
        "old_survey_number": "59/1"
    },
    timeout=30,
)
body = r.json()
print(body["status"], body["credits_charged"], body["data"])

const res = await fetch("https://verified.realestate/api/v1/tools/survey_history", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.LANDLENS_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "direction": "old_to_current",
    "district_code": "35",
    "taluk_code": "13",
    "town_code": "005",
    "old_survey_number": "59/1"
  }),
});
const body = await res.json();
console.log(body.status, body.credits_charged, body.data);

My grandfather's deed says R.S. 59/1 in Pallavaram, but the patta has a T.S. number. Which current parcels came from 59/1?

Your AI resolves the town, says the price, and lists the parcels that carry the old number.

Responses

Every answer has the same envelope. What status can say for this call:

status	What it means
`ok`	At least one parcel matched. Charged 1 credit.
`not_found`	No parcel matches, a required code is missing, or the register could not be reached. Nothing is charged.
`invalid_args`	direction, district_code or taluk_code is missing.
`insufficient_credits`	The account does not hold enough credits for the call.

Where the data comes from

Register

The revenue A-register of Tamil Nadu villages, which keeps against each sub-division the parent number it was carved from, and the town survey land register (TSLR), which keeps against each town survey parcel the revenue survey number it replaced.

Coverage

Village survey land and town survey land in every district we hold the registers for. A parcel whose entry leaves the earlier number blank is reported as having none recorded.

How current

Read from our copy of the registers, refreshed from the revenue department's registers.

How we read it

An old number is matched exactly as the register stores it first, then by its stem, so 186/4 also finds parcels recorded against 186. Each match says what kind of earlier number it is: a parent sub-division of the same survey, or a pre-renumbering survey number.

Who uses it

Advocates

Link a parent deed's old survey number to the parcels in today's register before writing a title opinion.

EC searches

Find the earlier number of a parcel so the encumbrance search covers the years before the renumbering.

Families

Work out which current parcels an inherited old survey number now covers.

Limits and good practice

A parcel listed is one the register derives from the old number. Which one a deed actually conveys is settled by its schedule and the FMB, not by the list.
PT (part) on an old number means the old field was split among several current parcels.
In a village the "old number" is often the parent sub-division, not a pre-UDR number; kind says which.
Where the register leaves the earlier number blank, nothing can be traced from it. For towns, try correlation_statement.

Pricing

1 credit per answer

Each call costs 1 credit when a parcel is found; nothing when none is. Credits come from the same LandLens wallet as the chat and the minis. How billing works.

Calling at volume?

For thousands of calls a month, a portfolio sweep or a platform built on these registers, we quote a customised bulk price, with invoicing to match.

WhatsApp 99961 29996

Questions

Is there an API for survey number history in Tamil Nadu?

Yes, this one. It traces an old survey number to the current parcels, or a current number to its earlier one, from the revenue registers.

What is UDR?

The Updating Registry scheme (from 1 June 1979 to about 1987) re-measured ryotwari villages outside Madras, the Nilgiris and Kanyakumari and issued fresh A-registers and FMBs. Many survey numbers changed then; town survey later replaced revenue numbers with T.S. numbers in towns.

How is this different from old_survey_to_current?

Both read the registers' earlier-number fields. This one also matches village land by the parent number's stem and labels the kind of earlier number, and is charged on result. old_survey_to_current returns fuller parcel detail and costs nothing.

What does it cost?

Each call costs 1 credit when a parcel is found, and nothing when none is.