{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://w3id.org/extendedmatrix/schemas/em.v1.1.schema.json",
  "$comment": "PUBLISHED COPY. Source of truth: https://github.com/ExtendedMatrix/s3Dgraphy, spec/em-json/em.v1.1.schema.json, commit 8209cab. Do not edit it here: edit it there and republish (spec/em-json/tools/publish_site.py), or the two drift apart.",
  "title": "em.json 1.1 — the Extended Matrix container",
  "description": "An em.json document is a CONTAINER: a header and one or more graphs, each with its nodes, edges and, optionally, its layout. Special members (the shelf, the DTC corpus, the periodizations) are graphs marked by data.em_collection. Readers MUST ignore keys they do not know; writers of the official tools never write keys prefixed 'x-', which are reserved to third-party extensions. The flat single-graph form of 1.0 ({header, graph}) is described by em.v1.schema.json and is still read by every conforming reader. Specification: https://w3id.org/extendedmatrix/spec/em-json/ — editor Emanuel Demetrescu (CNR-ISPC). This schema is dedicated to the public domain (CC0 1.0).",
  "type": "object",
  "required": [
    "header",
    "graphs"
  ],
  "properties": {
    "header": {
      "$ref": "#/$defs/header"
    },
    "graphs": {
      "type": "object",
      "description": "The members of the container, keyed by member id. A study graph's member id is its graph_id; the special members use conventional ids (shelf, dtc, periodizations) but are recognised by data.em_collection, never by the id.",
      "minProperties": 1,
      "additionalProperties": {
        "$ref": "#/$defs/member"
      }
    },
    "active_graph_id": {
      "type": "string",
      "description": "The study graph that was in front when the file was saved. A reader that finds no such member falls back to the first study graph."
    },
    "layout": {
      "$ref": "#/$defs/layout",
      "description": "A COPY of the active graph's layout, for readers that know only one layout per file (files before 2 Oct 2026, Heriverse). The member's own layout wins."
    },
    "version": {
      "$ref": "#/$defs/project_version"
    }
  },
  "$defs": {
    "text": {
      "description": "A text. Writers omit an empty value; readers treat null as absent.",
      "type": [
        "string",
        "null"
      ]
    },
    "header": {
      "type": "object",
      "required": [
        "format",
        "version"
      ],
      "properties": {
        "format": {
          "const": "em.json"
        },
        "version": {
          "type": "string",
          "pattern": "^1\\.[0-9]+(\\.[0-9]+)?$",
          "description": "The version of the FORM (semver): a reader refuses a MAJOR it does not know and reads every minor of its major. 1.0 = the flat form and the container written before this specification; 1.1 = the container as specified here."
        },
        "schema_version": {
          "type": "integer",
          "minimum": 0,
          "description": "The version of the CONTENT within the form, an integer that grows when a migration may need to key off it (absent = 0, a file older than the field). Never a reason to refuse a file."
        },
        "generator": {
          "type": "object",
          "properties": {
            "tool": {
              "type": "string"
            },
            "version": {
              "type": "string"
            }
          }
        },
        "last_editor": {
          "type": "string",
          "description": "The application that last saved the file, when it is not the generator (e.g. 'EMStudio 1.6.0-dev.58')."
        },
        "datamodel_versions": {
          "type": "object",
          "description": "The versions of the EM datamodels the content follows: nodes, connections, qualia.",
          "additionalProperties": {
            "type": "string"
          }
        },
        "ontology_versions": {
          "type": "object",
          "description": "The versions of the ontologies the datamodels map to (CIDOC-CRM, CRMarchaeo, CRMem…).",
          "additionalProperties": {
            "type": "string"
          }
        },
        "title": {
          "$ref": "#/$defs/text"
        },
        "name": {
          "$ref": "#/$defs/text"
        },
        "description": {
          "$ref": "#/$defs/text"
        },
        "visibility": {
          "type": "string",
          "description": "Who may read the study without a token: public, restricted (the default when absent), private."
        },
        "kind": {
          "type": "string",
          "description": "What the study is about: site (the default) or landscape."
        },
        "composition": {
          "type": "array",
          "description": "A landscape cites the studies it is made of: references, never copies. Each item is a string or {id, code, title}. 'part_studies' is an older name, read only.",
          "items": {
            "anyOf": [
              {
                "type": "string"
              },
              {
                "type": "object",
                "properties": {
                  "id": {
                    "type": "string"
                  },
                  "code": {
                    "type": "string"
                  },
                  "em_id": {
                    "type": "string"
                  },
                  "title": {
                    "type": "string"
                  }
                }
              }
            ]
          }
        },
        "owner": {
          "type": "string",
          "description": "The account that owns the study on a StratiGraph node (written by the server)."
        },
        "embargo": {
          "description": "An embargo set on a StratiGraph node: a date (ISO 8601) or an object the server defines. Licence and embargo of the CONTENT are nodes of the graph, not header keys.",
          "type": [
            "string",
            "object",
            "null"
          ]
        },
        "room": {
          "type": "object",
          "description": "Where the study is shared: {node, room_id} (written by EM Tools).",
          "properties": {
            "node": {
              "type": "string"
            },
            "room_id": {
              "type": "string"
            }
          }
        }
      }
    },
    "member": {
      "type": "object",
      "description": "One graph of the container.",
      "required": [
        "nodes",
        "edges"
      ],
      "properties": {
        "graph_id": {
          "type": "string",
          "description": "The graph's id; when absent the member id is used."
        },
        "code": {
          "type": "string",
          "description": "The study's code (GT16), a mirror of StudyNode.data.code written at every save; the study node wins on read."
        },
        "code_proposed": {
          "type": "boolean",
          "description": "Present (true) while the code is a proposal nobody confirmed."
        },
        "name": {
          "$ref": "#/$defs/text"
        },
        "description": {
          "$ref": "#/$defs/text"
        },
        "data": {
          "type": "object",
          "description": "Graph-level data. data.em_collection marks a special member.",
          "properties": {
            "em_collection": {
              "type": "string",
              "description": "ShelfGraph (the project shelf: authors, licences, shared documents), DTCCorpus (the documentation: acquisitions, transformations, the resources they are about), Periodizations (the shared measures of time: periodizations and their horizons). A reader that does not know a value treats the member as an ordinary graph."
            },
            "active_periodization": {
              "type": "string",
              "description": "In the Periodizations member: the id of the periodization in use."
            }
          }
        },
        "nodes": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/node"
          }
        },
        "edges": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/edge"
          }
        },
        "links": {
          "type": "array",
          "description": "Relations from a node of this graph to a node of ANOTHER graph of the same container (the address graph → node). A broken link is reported, never a reason to refuse the file.",
          "items": {
            "$ref": "#/$defs/link"
          }
        },
        "layout": {
          "$ref": "#/$defs/layout"
        }
      }
    },
    "node": {
      "type": "object",
      "required": [
        "id",
        "node_type"
      ],
      "properties": {
        "id": {
          "type": "string",
          "description": "Stable identifier (a UUID for nodes born in the official tools)."
        },
        "node_type": {
          "type": "string",
          "description": "The type, as named by the EM node datamodel (US, USVs, EpochNode, property, document, geo_position, periodization, horizon…). A reader that does not know a type keeps the node as a generic one."
        },
        "name": {
          "$ref": "#/$defs/text"
        },
        "description": {
          "$ref": "#/$defs/text"
        },
        "data": {
          "type": "object",
          "description": "The node's fields, as declared by the node datamodel for its type."
        }
      }
    },
    "edge": {
      "type": "object",
      "required": [
        "id",
        "edge_type",
        "source",
        "target"
      ],
      "properties": {
        "id": {
          "type": "string"
        },
        "edge_type": {
          "type": "string",
          "description": "The relation, as named by the EM connections datamodel (is_after, has_same_time, abuts, has_property, extracted_from…)."
        },
        "source": {
          "type": "string",
          "description": "The id of a node of the same graph."
        },
        "target": {
          "type": "string",
          "description": "The id of a node of the same graph."
        },
        "attributes": {
          "$ref": "#/$defs/edge_attributes"
        }
      }
    },
    "edge_attributes": {
      "type": "object",
      "description": "Optional facts about the edge itself (since schema_version 1).",
      "properties": {
        "origin": {
          "enum": [
            "derived",
            "user",
            "imported"
          ],
          "description": "On a relative-chronology edge (is_after, has_same_time, changed_from): computed from the physical relations, written by a person, or read from another software's file."
        },
        "derived": {
          "type": "boolean",
          "description": "The edge was computed by a propagation, not drawn."
        },
        "derived_from": {
          "description": "What a derived edge stands for: the id of the edge it was propagated from, or the ids of the physical relations it was derived from.",
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "array",
              "items": {
                "type": "string"
              }
            }
          ]
        },
        "inherited": {
          "type": "boolean"
        },
        "compacted": {
          "type": "boolean"
        },
        "injected_by": {
          "type": "string"
        },
        "role": {
          "type": "string"
        },
        "path": {
          "type": "string"
        },
        "original_edge_id": {
          "type": "string"
        },
        "original_source_id": {
          "type": "string"
        },
        "original_target_id": {
          "type": "string"
        },
        "created_by": {
          "type": "string",
          "description": "Editorial stamp: who drew the edge (as on nodes, in data)."
        },
        "created_at": {
          "type": "string",
          "description": "Editorial stamp: when (ISO 8601)."
        },
        "modified_by": {
          "type": "string"
        },
        "modified_at": {
          "type": "string"
        },
        "removed": {
          "description": "Tombstone of a removed edge (collaborative editing): the edge stays in the file, marked, so that a merge does not bring it back.",
          "type": [
            "object",
            "boolean"
          ]
        }
      }
    },
    "link": {
      "type": "object",
      "required": [
        "id",
        "edge_type",
        "source",
        "target"
      ],
      "properties": {
        "id": {
          "type": "string"
        },
        "edge_type": {
          "type": "string"
        },
        "source": {
          "type": "string",
          "description": "The id of a node of THIS graph."
        },
        "target": {
          "type": "object",
          "required": [
            "graph_id",
            "node_id"
          ],
          "properties": {
            "graph_id": {
              "type": "string"
            },
            "node_id": {
              "type": "string"
            }
          }
        },
        "attributes": {
          "$ref": "#/$defs/edge_attributes"
        }
      }
    },
    "position": {
      "type": "object",
      "required": [
        "x",
        "y"
      ],
      "properties": {
        "x": {
          "type": "number"
        },
        "y": {
          "type": "number"
        },
        "w": {
          "type": "number"
        },
        "h": {
          "type": "number"
        }
      }
    },
    "layout": {
      "type": "object",
      "description": "How a graph is drawn. Optional and reconstructable: a reader may lay the graph out afresh.",
      "properties": {
        "canvas": {
          "type": "object",
          "properties": {
            "title": {
              "$ref": "#/$defs/text"
            },
            "width": {
              "type": "number"
            },
            "height": {
              "type": "number"
            }
          }
        },
        "swimlanes": {
          "type": "array",
          "description": "The rows of the matrix, one per epoch.",
          "items": {
            "type": "object",
            "required": [
              "epoch_id",
              "order"
            ],
            "properties": {
              "epoch_id": {
                "type": "string"
              },
              "order": {
                "type": "integer"
              },
              "y": {
                "type": "number"
              },
              "height": {
                "type": "number"
              }
            }
          }
        },
        "sectors": {
          "type": "array",
          "description": "The columns of the matrix.",
          "items": {
            "type": "object",
            "required": [
              "id",
              "order"
            ],
            "properties": {
              "id": {
                "type": "string"
              },
              "order": {
                "type": "integer"
              },
              "x": {
                "type": "number"
              },
              "width": {
                "type": "number"
              }
            }
          }
        },
        "positions": {
          "type": "object",
          "description": "Node id → its box.",
          "additionalProperties": {
            "$ref": "#/$defs/position"
          }
        },
        "folded_groups": {
          "type": "array",
          "items": {
            "type": "string"
          }
        },
        "group_spaces": {
          "type": "object",
          "description": "Group id → the positions inside the group's own space.",
          "additionalProperties": {
            "type": "object",
            "properties": {
              "positions": {
                "type": "object",
                "additionalProperties": {
                  "$ref": "#/$defs/position"
                }
              }
            }
          }
        },
        "edge_routes": {
          "type": "object",
          "description": "Edge id → the bends of its line, [x, y] points.",
          "additionalProperties": {
            "type": "array",
            "items": {
              "type": "array",
              "prefixItems": [
                {
                  "type": "number"
                },
                {
                  "type": "number"
                }
              ]
            }
          }
        },
        "pinned": {
          "type": "array",
          "description": "Node ids that keep their exact box through a re-layout.",
          "items": {
            "type": "string"
          }
        },
        "anchors": {
          "type": "array",
          "description": "A node drawn next to another one (a date beside its unit): the corner of 'to' it sits at and the offset.",
          "items": {
            "type": "object",
            "required": [
              "node",
              "to"
            ],
            "properties": {
              "node": {
                "type": "string"
              },
              "to": {
                "type": "string"
              },
              "corner": {
                "type": "string"
              },
              "dx": {
                "type": "number"
              },
              "dy": {
                "type": "number"
              }
            }
          }
        },
        "sketches": {
          "type": "array",
          "description": "Shapes placed in the 3D space and not yet proxies of a unit (EMStudio): the person's work, saved with the view.",
          "items": {
            "type": "object"
          }
        }
      }
    },
    "project_version": {
      "type": "object",
      "description": "Which revision of the WORK this file is (not of the format).",
      "required": [
        "number"
      ],
      "properties": {
        "number": {
          "type": "integer",
          "minimum": 1
        },
        "id": {
          "type": "string",
          "description": "Content digest of this version, 'sha256:<12 hex>'."
        },
        "was_revision_of": {
          "type": "string"
        },
        "modified_at": {
          "type": "string"
        }
      }
    }
  }
}