{ "openapi": "3.1.1", "info": { "title": "Cartograph True Size of Countries (Mercator comparer) API", "version": "1.0.0", "summary": "Move a country to another latitude and see its true size against the Mercator map.", "description": "Every endpoint performs the same calculation as the human page and returns inputs, result, units, assumptions, sources, warnings and computedAt. MCP endpoint: /mcp." }, "servers": [ { "url": "https://cartographtruesize.usefulweb.app" } ], "paths": { "/api/v1/calculate": { "post": { "operationId": "calculate", "summary": "Move a country to another latitude and see its true size against the Mercator map.", "description": "Moves a country outline (Natural Earth admin-0) to any place on the globe while keeping its true shape and area, and shows how big it looks on a Web-Mercator map at home and at the new place, next to its real geodesic area and an optional second country. It is the true-size engine of the Cartograph app.\n\nMethodology:\n- Outlines: Natural Earth 1:110m admin-0 countries (public domain), the same file as the Geo Data Visualizer; small countries and islands below that scale are missing.\n- Moving: every vertex keeps its geodesic distance and azimuth from the anchor (Karney’s inverse problem at home, direct problem at the new place, WGS84). On a sphere this is an exact rotation; on the ellipsoid the true area changes by well under 1 % — both areas are reported.\n- True area: geodesic polygon area on WGS84 (outer rings minus holes). Apparent area: planar area of the outline in Web Mercator at equator scale, which grows with sec²(latitude) — 4 × at 60°.", "tags": [ "apps" ], "x-mcp-tool": "cartograph_true_size", "x-owner-app": "cartograph", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CartographTrueSizeInput" }, "examples": { "example1": { "summary": "Greenland moved to the equator, compared with DR Congo", "value": { "country": "GRL", "target": "2, 20", "compare": "COD" } }, "example2": { "summary": "Brazil laid over Europe", "value": { "country": "Brazil", "target": "51, 12" } } } } } }, "responses": { "200": { "description": "Calculation result envelope.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CartographTrueSizeResult" } } } }, "400": { "description": "Malformed JSON body.", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "422": { "description": "Invalid input (see errors[]).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "429": { "description": "Rate limit exceeded (see Retry-After).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } } } } }, "/api/v1/tool": { "get": { "operationId": "getToolDefinition", "summary": "Inputs, output schema and examples for this tool", "responses": { "200": { "description": "Tool definition.", "content": { "application/json": { "schema": { "type": "object" } } } } } } } }, "components": { "schemas": { "Problem": { "type": "object", "description": "RFC 9457 problem details. 422 responses include per-field `errors`.", "required": [ "type", "title", "status", "detail" ], "properties": { "type": { "type": "string" }, "title": { "type": "string" }, "status": { "type": "integer" }, "detail": { "type": "string" }, "code": { "type": "string" }, "errors": { "type": "array", "items": { "type": "object", "required": [ "field", "message" ], "properties": { "field": { "type": "string" }, "message": { "type": "string" } } } } } }, "CartographTrueSizeInput": { "type": "object", "additionalProperties": false, "properties": { "country": { "title": "Country (English name or ISO code)", "type": "string", "maxLength": 60, "default": "GRL" }, "target": { "title": "Move it to", "description": "Coordinate of the new centre (anchor = centre of the bounding box of the largest part).", "type": "string", "default": "2, 20" }, "rotationDeg": { "title": "Rotation (clockwise)", "type": "number", "minimum": -180, "maximum": 180, "default": 0, "x-unit": "°" }, "compare": { "title": "Compare with (optional)", "description": "A second country drawn at home and compared by true area.", "type": "string", "maxLength": 60, "default": "" } }, "required": [] }, "CartographTrueSizeResult": { "type": "object", "additionalProperties": false, "required": [ "schemaVersion", "tool", "computedAt", "inputs", "summary", "result", "units", "assumptions", "sources", "warnings", "presentation", "links" ], "properties": { "schemaVersion": { "type": "string", "const": "1.0" }, "tool": { "type": "object", "additionalProperties": false, "required": [ "id", "name", "version" ], "properties": { "id": { "type": "string" }, "name": { "type": "string" }, "version": { "type": "string" } } }, "computedAt": { "type": "string", "format": "date-time" }, "inputs": { "type": "object", "description": "Normalised inputs actually used, including applied defaults." }, "summary": { "type": "string" }, "result": { "type": "object", "additionalProperties": false, "required": [ "country", "iso3", "anchor", "target", "rotationDeg", "trueAreaKm2", "movedTrueAreaKm2", "apparentHomeKm2", "apparentTargetKm2", "apparentChange", "compare", "geojson" ], "properties": { "country": { "type": "string" }, "iso3": { "type": "string" }, "anchor": { "type": "object", "additionalProperties": false, "required": [ "lat", "lon" ], "properties": { "lat": { "type": "number" }, "lon": { "type": "number" } } }, "target": { "type": "object", "additionalProperties": false, "required": [ "lat", "lon" ], "properties": { "lat": { "type": "number" }, "lon": { "type": "number" } } }, "rotationDeg": { "type": "number" }, "trueAreaKm2": { "type": "number" }, "movedTrueAreaKm2": { "type": "number" }, "apparentHomeKm2": { "type": "number", "description": "Planar Web-Mercator area at home, km² at equator scale." }, "apparentTargetKm2": { "type": "number" }, "apparentChange": { "type": "number", "description": "Apparent area at the new place ÷ apparent area at home." }, "compare": { "type": [ "object", "null" ], "additionalProperties": false, "required": [ "country", "iso3", "trueAreaKm2", "ratio" ], "properties": { "country": { "type": "string" }, "iso3": { "type": "string" }, "trueAreaKm2": { "type": "number" }, "ratio": { "type": "number", "description": "True area of the country ÷ true area of the comparison country." } } }, "geojson": { "type": "object", "additionalProperties": false, "required": [ "artifactId", "filename", "mime", "bytes", "sha256", "path" ], "properties": { "artifactId": { "type": "string" }, "filename": { "type": "string" }, "mime": { "type": "string" }, "bytes": { "type": "integer" }, "sha256": { "type": "string" }, "path": { "type": "string", "description": "Download path on the same site (valid for about 2 hours)." } } } } }, "units": { "type": "object", "additionalProperties": { "type": "string" } }, "assumptions": { "type": "array", "items": { "type": "string" } }, "sources": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "title" ], "properties": { "title": { "type": "string" }, "url": { "type": "string" }, "publisher": { "type": "string" }, "retrievedAt": { "type": "string" }, "note": { "type": "string" } } } }, "warnings": { "type": "array", "items": { "type": "string" } }, "presentation": { "type": "array", "items": { "type": "object" }, "description": "Display blocks used by the human page (same data)." }, "links": { "type": "object", "additionalProperties": false, "required": [ "human", "api", "openapi", "methodology" ], "properties": { "human": { "type": "string", "format": "uri" }, "api": { "type": "string", "format": "uri" }, "openapi": { "type": "string", "format": "uri" }, "methodology": { "type": "string", "format": "uri" } } } } } } } }