schema.json

{
  "$schema":"http://json-schema.org/draft-07/schema#",
  "$id":"schema.json#",
  "title":"Projection Extension",
  "description":"STAC Projection Extension to a STAC Item",
  "allOf":[
    {
      "$ref": "../../../item-spec/json-schema/item.json"
    },
    {
      "$ref":"#/definitions/proj"
    }
  ],
  "definitions":{
    "proj":{
      "type": "object",
      "required": [
        "stac_extensions",
        "properties"
      ],
      "properties":{
        "stac_extensions": {
          "type": "array",
          "contains": {
            "const": "projection"
          }
        },
        "properties":{
          "type":"object",
          "required":[
            "proj:epsg"
          ],
          "properties":{
            "proj:epsg":{
              "title":"EPSG code",
              "type":[
                "integer",
                "null"
              ]
            },
            "proj:wkt2":{
              "title":"Coordinate Reference System in WKT2 format",
              "type":[
                "string",
                "null"
              ]
            },
            "proj:projjson": {
              "title":"Coordinate Reference System in PROJJSON format",
              "oneOf": [
                {
                  "$ref": "https://proj.org/schemas/v0.1/projjson.schema.json"
                },
                {
                  "type": "null"
                }
              ]
            },
            "proj:geometry":{
              "title":"Geometry",
              "oneOf": [
                {
                  "$ref": "https://geojson.org/schema/Polygon.json"
                }
              ]
            },
            "proj:bbox":{
              "title":"Extent",
              "type":"array",
              "minItems":4,
              "maxItems":6,
              "items":{
                "type":"number"
              }
            },
            "proj:centroid":{
              "title":"Centroid",
              "type":"object",
              "required": [
                "lat",
                "lon"
              ],
              "properties": {
                "lat": {
                  "type": "number",
                  "minimum": -90,
                  "maximum": 90
                },
                "lon": {
                  "type": "number",
                  "minimum": -180,
                  "maximum": 180
                }
              }
            },
            "proj:shape":{
              "title":"Shape",
              "type":"array",
              "minItems":2,
              "maxItems":2,
              "items":{
                "type":"integer"
              }
            },
            "proj:transform":{
              "title":"Transform",
              "type":"array",
              "minItems":6,
              "maxItems":9,
              "items":{
                "type":"number"
              }
            }
          }
        }
      }
    }
  }
}