From 2fc18e847eb2f7541d28137c2ee932f947c45998 Mon Sep 17 00:00:00 2001
From: Amir Hakim <50393714+amiroo4@users.noreply.github.com>
Date: Wed, 24 Sep 2025 09:23:43 +0200
Subject: [PATCH] Create LinkedGeoreference.ifcx

This document proposes a linked georeferencing approach for IFC 5. CRSs are referenced externally toPROJJSON, which encodes CRS definitions, transformations, and coordinate operations in JSON. The schema is designed to be applicable across all georeferencing use cases and to remain independent of any specific file instance.
---
 .../LinkedGeoreference.ifcx                   | 131 ++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 examples/PCERT-Sample-Scene/LinkedGeoreference.ifcx

diff --git a/examples/PCERT-Sample-Scene/LinkedGeoreference.ifcx b/examples/PCERT-Sample-Scene/LinkedGeoreference.ifcx
new file mode 100644
index 00000000..bb244155
--- /dev/null
+++ b/examples/PCERT-Sample-Scene/LinkedGeoreference.ifcx
@@ -0,0 +1,131 @@
+{
+  "header": {
+    "id": "LinkedGeoreference.ifcx",
+    "ifcxVersion": "ifcx_alpha",
+    "dataVersion": "1.0.0",
+    "author": "On-Track",
+    "timestamp": "time string"
+  },
+  "imports": [],
+    "schemas": {
+        "crsType::GeographicCRS": {
+            "value": {
+            "dataType": "Object",
+            "objectRestrictions": {
+                "values": {
+                "crsRef": { "dataType": "String" },
+                "uri": { "dataType": "String" },
+                "latitude":  { "dataType": "Real", "quantityKind": "Angle" },
+                "longitude": { "dataType": "Real", "quantityKind": "Angle" }
+                }
+            }
+            }
+        },
+        "crsType::ProjectedCRS": {
+            "value": {
+            "dataType": "Object",
+            "objectRestrictions": {
+                "values": {
+                "crsRef":   { "dataType": "String" },
+                "uri": { "dataType": "String" },
+                "eastings": { "dataType": "Real", "quantityKind": "Length" },
+                "northings":{ "dataType": "Real", "quantityKind": "Length" }
+                }
+            }
+            }
+        },
+        "crsType::VerticalCRS": {
+            "value": {
+            "dataType": "Object",
+            "objectRestrictions": {
+                "values": {
+                "crsRef": { "dataType": "String" },
+                "uri": { "dataType": "String" },
+                "height": { "dataType": "Real", "quantityKind": "Length" }
+                }
+            }
+            }
+        },
+            "crsType::CompoundCRS": {
+            "value": {
+            "dataType": "Object",
+            "objectRestrictions": {
+                "values": {
+                "crsRef":   { "dataType": "String" },
+                "uri": { "dataType": "String" },
+                "eastings": { "dataType": "Real", "quantityKind": "Length" },
+                "northings":{ "dataType": "Real", "quantityKind": "Length" },
+                "height":   { "dataType": "Real", "quantityKind": "Length" }
+                }
+            }
+            }
+        }
+
+        },
+  "data": [
+    {
+      "path": "8f104696-d1c4-4375-8b96-fdc8f2d0c2e8",
+      "attributes": {
+        "crsType::ProjectedCRS": {
+          "crsRef": "EPSG:32760",
+          "uri": "https://spatialreference.org/ref/epsg/32760/projjson.json",
+          "eastings": 729013.349,
+          "northings": 9063992.685
+        }
+      }
+    },
+    {
+      "path": "8f104696-d1c4-4375-8b96-fdc8f2d0c2e8",
+      "attributes": {
+        "crsType::GeographicCRS": {
+        "crsRef": "EPSG:4326",
+        "uri": "https://spatialreference.org/ref/epsg/4326/projjson.json",
+        "latitude": -8.46219994,
+        "longitude": 179.08014672
+        }
+      }
+    },
+    {
+      "path": "8f104696-d1c4-4375-8b96-fdc8f2d0c2e8",
+      "attributes": {
+        "crsType::VerticalCRS": {
+          "crsRef": "EPSG:3855",
+          "uri": "https://spatialreference.org/ref/epsg/3855/projjson.json",
+          "height": 1.3
+        }
+      }
+    },
+    {
+      "path": "cfb3708f-9272-42f6-90a9-1a48274f73c5",
+      "attributes": {
+        "crsType::ProjectedCRS": {
+          "crsRef": "EPSG:32760",
+          "uri": "https://spatialreference.org/ref/epsg/32760/projjson.json",
+          "eastings": 729011.226,
+          "northings": 9063960.608
+        }
+      }
+    },
+    {
+      "path": "cfb3708f-9272-42f6-90a9-1a48274f73c5",
+      "attributes": {
+        "crsType::GeographicCRS": {
+          "crsRef": "EPSG:4326",
+          "uri": "https://spatialreference.org/ref/epsg/4326/projjson.json",
+          "latitude": -8.46249,
+          "longitude": 179.080129
+        }
+      }
+    },
+    {
+      "path": "cfb3708f-9272-42f6-90a9-1a48274f73c5",
+      "attributes": {
+        "crsType::VerticalCRS": {
+          "crsRef": "EPSG:3855",
+          "uri": "https://spatialreference.org/ref/epsg/3855/projjson.json",
+          "height": 0
+        }
+      }
+    }
+  ]
+}