Layer operations

Simplify feature outlines

Lighter outlines: the lines or polygons of a layer simplified so no vertex moves more than a tolerance in metres.


REST	`POST https://mcp.terra-lab.ai/v1/tools/simplify_features`
MCP tool	`simplify_features` on `https://mcp.terra-lab.ai/mcp`
Group	Layer operations

Request

cURLPythonJavaScript

curl -X POST https://mcp.terra-lab.ai/v1/tools/simplify_features \
  -H "Authorization: Bearer $TERRALAB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"url":"https://mcp.terra-lab.ai/dl/geojson/TOKEN/buildings.geojson","tolerance_m":5}'

import os
import requests

response = requests.post(
    "https://mcp.terra-lab.ai/v1/tools/simplify_features",
    headers={"Authorization": f"Bearer {os.environ['TERRALAB_API_KEY']}"},
    json={
        "url": "https://mcp.terra-lab.ai/dl/geojson/TOKEN/buildings.geojson",
        "tolerance_m": 5,
    },
    timeout=120,
)
response.raise_for_status()
print(response.json()["structuredContent"])

const response = await fetch('https://mcp.terra-lab.ai/v1/tools/simplify_features', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.TERRALAB_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "url": "https://mcp.terra-lab.ai/dl/geojson/TOKEN/buildings.geojson",
    "tolerance_m": 5
  }),
});
const data = await response.json();
console.log(data.structuredContent);

Parameters

A JSON object in the request body; in an MCP client, the arguments of the tool call.

Name	Type	Required	Description
`file`	object	No	A file uploaded in the conversation (GeoJSON, KML, KMZ, GPX, zipped Shapefile, CSV or WKT).
`file.download_url`	string	Yes
`file.file_id`	string	Yes
`file.file_name`	string	No
`file.mime_type`	string	No
`url`	string	No	A public http(s) link to the features, or a TerraLab download link from an earlier answer.
`geojson`	object	No	The features as a GeoJSON FeatureCollection, Feature or geometry in WGS 84 (longitude, latitude).
`tolerance_m`	number	Yes	The largest allowed shift of the outline in metres. From 0.01 to 100000.
`formats`	array of string	No	Download formats. All five by default.
`title`	string	No	Name for the map and the output files.

Response

structuredContent holds the result, content the same result as text for a model, and isError is true when the tool refused the request or failed; then structuredContent.code, message and hint say what to change.

{
  "structuredContent": {
    "sources": [{ "name": "...", "licence": "...", "url": "..." }],
    "downloads": [{ "label": "...", "format": "...", "url": "...", "name": "..." }]
  },
  "content": [{ "type": "text", "text": "..." }],
  "isError": false
}

Every result lists its sources with their licence. File results come as downloads: each link builds its file when opened.

Errors

A missing key answers 401, an empty balance 402, too many calls 429. A call that fails or finds nothing is not counted. See Errors and rate limits.

Description for agents

The text the server gives an agent to decide when to call this tool:

Use this when the user wants lighter outlines: simplify the lines or polygons of a layer (an uploaded file, a link, inline GeoJSON or a TerraLab download link) so no vertex moves more than tolerance_m. Runs in a local equidistant projection; up to 20,000 features and 100,000 vertices. Returns the feature count, a map and GeoJSON, KML, Shapefile zip, GeoPackage and CSV downloads. Never use the user's current location unless they type it. Download links build their file when opened; no file is saved. The user opens the file in QGIS or any GIS: this server cannot load it into the user's own QGIS or any app on their computer. Never pass these links to open_gis_file: list every format the user needs in formats, in this one call. TerraLab reads the file or link to answer and keeps no copy.

Updated 2026-11-15