ifc2geojson

v1.3.8

Published

a month ago

Convert IFC (BIM) to GeoJSON (GIS) - Browser and Node.js compatible

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abdoulayediak

ifc geojson 3d converter bim gis geobim

ifc2geojson - IFC to GeoJSON Converter

This project provides tools to convert IFC (Industry Foundation Classes) models into 3D GeoJSON for GIS and web mapping applications. It includes a precision-aware GeoJSON exporter, IFC filtering, and utilities for generating GeoPackage schema from GeoJSON. See the live demo.

Features

Parses IFC data using web-ifc.
Converts IFC geometries into 3D GeoJSON using three.js.
Supports coordinate reference system (CRS) specification.
Provides GeoPackage property type extraction for database schema generation.
Reads and applies IfcMapConversion (IFC4) for direct georeferencing of models.
Allows filtering of IFC elements (include/exclude by class) when exporting to GeoJSON.
Improves coordinate precision with Float64Array geometry storage and georef offset strategy.
Offers both object and Blob outputs for easy integration in Node.js or browser contexts.

Installation

Install via npm:

npm install ifc2geojson

Usage

Importing

import {
  ifc2Geojson,
  ifc2GeojsonBlob,
  ifc2GeojsonWithFilter,
  ifc2GeojsonBlobWithFilter,
  getGeoPackagePropertiesFromGeoJSON,
  getElemsWithGeom
} from 'ifc2geojson';

Convert IFC → GeoJSON (object)

const crs = "urn:ogc:def:crs:EPSG::3857";
const ifcData: Uint8Array = /* load your IFC file */;

const geojson = await ifc2Geojson(ifcData, crs, (msg) => console.log(msg));
console.log(geojson);

Convert IFC → GeoJSON with Filtering

Filter IFC classes to include or exclude:

const toFilter = ["IfcWall", "IfcSlab"];

const geojson = await ifc2GeojsonWithFilter(
  ifcData,
  "urn:ogc:def:crs:EPSG::3857",
  toFilter,
  (msg) => console.log(msg)
);

Or directly get a Blob:

const blob = await ifc2GeojsonBlobWithFilter(ifcData, "urn:ogc:def:crs:EPSG::3857", toFilter);

Extract IFC element types that contain geometry

const elems = await getElemsWithGeom(ifcData);
console.log(elems);
// e.g., ["IfcWall", "IfcSlab", "IfcColumn"]

Extract GeoPackage Properties from GeoJSON

const properties = getGeoPackagePropertiesFromGeoJSON(geojson);
console.log(properties);
/*
[
  { name: "IfcEntity", dataType: "TEXT" },
  { name: "Name", dataType: "TEXT" },
  ...
]
*/

Browser Usage

To use this library directly in a browser environment, include the browser bundle (ifc2geojson.min.js) in your HTML and make sure to also host the required .wasm files (web-ifc.wasm, etc.) in the same directory or configure their paths properly. When all required files are properly imported in a browser environment, the API will be accessible via the global window.ifc2geojson object.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
</head>
<body>
  <input type="file" id="ifcInput" accept=".ifc" />

  <script src="path/to/ifc2geojson.min.js"></script>
  <script>
    document.getElementById("ifcInput").addEventListener("change", async (e) => {
      const file = e.target.files[0];
      const arrayBuffer = await file.arrayBuffer();
      const uint8 = new Uint8Array(arrayBuffer);
  
      const { ifc2GeojsonBlob } = window.ifc2geojson;
  
      const crs = "EPSG:4327";
      const blob = await ifc2GeojsonBlob(uint8, crs, (msg) => {
        console.log("Progress:", msg);
      });
  
      const url = URL.createObjectURL(blob);
      const a = document.createElement("a");
      a.href = url;
      a.download = file.name.replace(/\.ifc$/i, ".geojson");
      a.click();
    });
  </script>

</body>
</html>

API Reference

`ifc2Geojson(ifcData, crs?, msgCallback?)`

Parses IFC and returns a GeoJSON FeatureCollection.

ifcData: Uint8Array
crs: CRS string (default "urn:ogc:def:crs:EPSG::3857")
msgCallback: progress callback

`ifc2GeojsonWithFilter(ifcData, crs?, toFilter?, msgCallback?)`

Like ifc2Geojson but allows filtering by IFC class names.

`ifc2GeojsonBlob(ifcData, crs?, msgCallback?)`

Like ifc2Geojson, but returns a Blob.

`ifc2GeojsonBlobWithFilter(ifcData, crs?, toFilter?, msgCallback?)`

Blob version of the filtered exporter.

`getElemsWithGeom(ifcData)`

Returns IFC element type names that have geometry.

`getGeoPackagePropertiesFromGeoJSON(geojson)`

Analyzes a GeoJSON FeatureCollection and outputs property names and GeoPackage-compatible data types.

Acknowledgements

web-ifc — IFC parsing
three.js — 3D geometry processing
three-geojson-exporter — inspiration for exporter
geopackage-js — for GeoJSON → GeoPackage schema

License

This source code is licensed under the Mozilla Public License 2.0 (MPL-2.0).
See https://mozilla.org/MPL/2.0/.

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