{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "id": "https://raw.githubusercontent.com/fge/sample-json-schemas/master/geojson/geojson.json#",
  "title": "Geo JSON object",
  "description": "Schema for a Geo JSON object",
  "type": "object",
  "required": ["type"],
  "properties": {
    "crs": { "$ref": "#/definitions/crs" },
    "bbox": { "$ref": "#/definitions/bbox" }
  },
  "oneOf": [
    { "$ref": "#/definitions/geometry" },
    { "$ref": "#/definitions/geometryCollection" },
    { "$ref": "#/definitions/feature" },
    { "$ref": "#/definitions/featureCollection" }
  ],
  "definitions": {
    "geometryCollection": {
      "title": "GeometryCollection",
      "description": "A collection of geometry objects",
      "required": ["geometries"],
      "properties": {
        "type": { "enum": ["GeometryCollection"] },
        "geometries": {
          "type": "array",
          "items": { "$ref": "#/definitions/geometry" }
        }
      }
    },
    "feature": {
      "title": "Feature",
      "description": "A Geo JSON feature object",
      "required": ["geometry", "properties"],
      "properties": {
        "type": { "enum": ["Feature"] },
        "geometry": {
          "oneOf": [{ "type": "null" }, { "$ref": "#/definitions/geometry" }]
        },
        "properties": { "type": ["object", "null"] },
        "id": { "FIXME": "may be there, type not known (string? number?)" }
      }
    },
    "featureCollection": {
      "title": "FeatureCollection",
      "description": "A Geo JSON feature collection",
      "required": ["features"],
      "properties": {
        "type": { "enum": ["FeatureCollection"] },
        "features": {
          "type": "array",
          "items": { "$ref": "#/definitions/feature" }
        }
      }
    },
    "geometry": {
      "title": "geometry",
      "description": "One geometry as defined by GeoJSON",
      "type": "object",
      "required": ["type", "coordinates"],
      "oneOf": [
        {
          "title": "Point",
          "properties": {
            "type": { "enum": ["Point"] },
            "coordinates": {
              "$ref": "#/definitions/geometry/definitions/position"
            }
          }
        },
        {
          "title": "MultiPoint",
          "properties": {
            "type": { "enum": ["MultiPoint"] },
            "coordinates": {
              "$ref": "#/definitions/geometry/definitions/positionArray"
            }
          }
        },
        {
          "title": "LineString",
          "properties": {
            "type": { "enum": ["LineString"] },
            "coordinates": {
              "$ref": "#/definitions/geometry/definitions/lineString"
            }
          }
        },
        {
          "title": "MultiLineString",
          "properties": {
            "type": { "enum": ["MultiLineString"] },
            "coordinates": {
              "type": "array",
              "items": {
                "$ref": "#/definitions/geometry/definitions/lineString"
              }
            }
          }
        },
        {
          "title": "Polygon",
          "properties": {
            "type": { "enum": ["Polygon"] },
            "coordinates": {
              "$ref": "#/definitions/geometry/definitions/polygon"
            }
          }
        },
        {
          "title": "MultiPolygon",
          "properties": {
            "type": { "enum": ["MultiPolygon"] },
            "coordinates": {
              "type": "array",
              "items": { "$ref": "#/definitions/geometry/definitions/polygon" }
            }
          }
        }
      ],
      "definitions": {
        "position": {
          "description": "A single position",
          "type": "array",
          "minItems": 2,
          "items": [{ "type": "number" }, { "type": "number" }],
          "additionalItems": false
        },
        "positionArray": {
          "description": "An array of positions",
          "type": "array",
          "items": { "$ref": "#/definitions/geometry/definitions/position" }
        },
        "lineString": {
          "description": "An array of two or more positions",
          "allOf": [
            { "$ref": "#/definitions/geometry/definitions/positionArray" },
            { "minItems": 2 }
          ]
        },
        "linearRing": {
          "description": "An array of four positions where the first equals the last",
          "allOf": [
            { "$ref": "#/definitions/geometry/definitions/positionArray" },
            { "minItems": 4 }
          ]
        },
        "polygon": {
          "description": "An array of linear rings",
          "type": "array",
          "items": { "$ref": "#/definitions/geometry/definitions/linearRing" }
        }
      }
    },
    "crs": {
      "title": "crs",
      "description": "a Coordinate Reference System object",
      "type": ["object", "null"],
      "required": ["type", "properties"],
      "properties": {
        "type": { "type": "string" },
        "properties": { "type": "object" }
      },
      "additionalProperties": false,
      "oneOf": [
        { "$ref": "#/definitions/crs/definitions/namedCrs" },
        { "$ref": "#/definitions/crs/definitions/linkedCrs" }
      ],
      "definitions": {
        "namedCrs": {
          "properties": {
            "type": { "enum": ["name"] },
            "properties": {
              "required": ["name"],
              "additionalProperties": false,
              "properties": {
                "name": {
                  "type": "string",
                  "FIXME": "semantic validation necessary"
                }
              }
            }
          }
        },
        "linkedObject": {
          "type": "object",
          "required": ["href"],
          "properties": {
            "href": {
              "type": "string",
              "format": "uri",
              "FIXME": "spec says \"dereferenceable\", cannot enforce that"
            },
            "type": {
              "type": "string",
              "description": "Suggested values: proj4, ogjwkt, esriwkt"
            }
          }
        },
        "linkedCrs": {
          "properties": {
            "type": { "enum": ["link"] },
            "properties": {
              "$ref": "#/definitions/crs/definitions/linkedObject"
            }
          }
        }
      }
    },
    "bbox": {
      "description": "A bounding box as defined by GeoJSON",
      "FIXME": "unenforceable constraint: even number of elements in array",
      "type": "array",
      "items": { "type": "number" }
    }
  }
}