API & MCP

Everything a person can do on GISela Buffer, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://giselabuffer.usefulweb.site/api/v1/calculate – run GISela Buffer
GET https://giselabuffer.usefulweb.site/api/v1/tool – inputs, output schema, examples
OpenAPI 3.1: /openapi.json · /openapi.yaml
Errors: application/problem+json; 422 includes per-field errors.

GISela Buffer

Creates buffer polygons at a true distance in metres around every feature of GeoJSON, KML, GPX, CSV or shapefile data: circles around points, corridors around lines, grown or shrunk polygons. Overlapping zones can be merged into one area. Returns GeoJSON, the ellipsoidal area of each zone and a map preview.

Inputs of GISela Buffer
Field	Type	Default	Description
`data`	textarea	—	Data. GeoJSON, TopoJSON, KML, GPX, CSV (lat/lon, x/y or a WKT column) or WKT lines. Or upload a file below.
`file`	file	—	File (optional). Used instead of the pasted text. Shapefiles: put .shp, .dbf and .prj into one ZIP.
`from`	text	"auto"	Coordinate system of the data. “auto” reads it from the file (.prj, GeoJSON crs); otherwise an EPSG code such as 2056, 25832 or 27700. Without information the data is read as WGS 84 longitude/latitude.
`distance`	number	300	Distance (metres). Negative values shrink polygons.
`segments`	integer	32	Segments per circle. More segments = rounder curves, bigger files.
`dissolve`	boolean	false	Merge overlapping zones into one

Example request

300 m around seven tram stops, merged

curl -X POST https://giselabuffer.usefulweb.site/api/v1/calculate -H 'content-type: application/json' -d '{"data":"{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[7.992,47.1215]},\"properties\":{\"name\":\"Weiher\"}},{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[7.999,47.126]},\"properties\":{\"name\":\"Altstadt\"}},{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[8.006,47.129]},\"properties\":{\"name\":\"Marktplatz\"}},{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[8.012,47.1335]},\"properties\":{\"name\":\"Bahnhof\"}},{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[8.018,47.137]},\"properties\":{\"name\":\"Nordring\"}},{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[8.025,47.14]},\"properties\":{\"name\":\"Rebhalde\"}},{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[8.031,47.1405]},\"properties\":{\"name\":\"Endstation Ost\"}}]}","distance":300,"dissolve":true}'

Every result contains

inputs (normalised, defaults applied), summary, result (validated against the published schema), units, assumptions, sources, warnings, computedAt and links.

MCP (Model Context Protocol)

Streamable HTTP endpoint: https://giselabuffer.usefulweb.site/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: gisela_buffer
Local stdio connector: node src/mcp-stdio.ts --tool=gisela-buffer

{
  "mcpServers": {
    "gisela-buffer": { "type": "http", "url": "https://giselabuffer.usefulweb.site/mcp" }
  }
}