landxml

LandXML Parser for Contour GeoJSON and 3D Models

Easily transform LandXML surfaces into GeoJSON contours or GLB 3D models for use in ThreeJS, Cesium, QGIS, or any popular 3D/GIS software.

Features

• toGlbAndContours — Generate both a GLB model and GeoJSON contours in a single pass (fastest when you need both outputs).
• toGlb — Generate a GLB 3D model from LandXML surfaces.
• toGeojsonContours — Convert LandXML surfaces into contour line GeoJSON.
• reprojectGeoJson — Reproject GeoJSON coordinates to any projection using mproj.

Installation

npm install landxml

Examples

Get contours and a GLB model together (recommended)

When you need both outputs, use toGlbAndContours — it parses the XML once and shares computed data between both outputs, making it significantly faster than calling toGlb and toGeojsonContours separately.

import { toGlbAndContours, reprojectGeoJson } from "landxml";

const landXmlString = `<?xml version="1.0"?>...<LandXML>...</LandXML>`;

const surfaces = await toGlbAndContours(
  landXmlString,
  2, // contour interval (LandXML units)
  true, // generate outline
  "auto", // GLB center: "auto" | "origin" | [x, y]
);

const { glb, center, geojson, wktString, download } = surfaces[0];

// Download the GLB file in the browser
download();

// Reproject contours from the LandXML CRS to WGS84
const reprojected = reprojectGeoJson(geojson, wktString, "WGS84", false);

Get GeoJSON contours only

import { toGeojsonContours, reprojectGeoJson } from "landxml";

const landXmlString = `<?xml version="1.0"?>...<LandXML>...</LandXML>`;

const surfaces = await toGeojsonContours(
  landXmlString,
  2, // contour interval (LandXML units)
  true, // include surface outline as a z=0 feature
);

const { geojson, wktString } = surfaces[0];

// Reproject from the LandXML coordinate system to WGS84 for web mapping
const reprojected = reprojectGeoJson(geojson, wktString ?? "WGS84", "WGS84", false);

console.log(reprojected.features.length); // number of contour + outline features

Convert to a GLB 3D model

import { toGlb } from "landxml";

const landXmlString = `<?xml version="1.0"?>...<LandXML>...</LandXML>`;

const surfaces = await toGlb(
  landXmlString,
  "auto", // centre strategy: "auto" | "origin" | [x, y]
);

const { glb, center, download } = surfaces[0];

// Trigger a browser download of the .glb file
download();

// Or use the raw binary (Uint8Array) directly — e.g. load into Three.js
const loader = new GLTFLoader();
loader.parse(glb.buffer, "", (gltf) => {
  scene.add(gltf.scene);
});

Work with a specific surface in a multi-surface LandXML

LandXML files can contain multiple surfaces. Use surfaceId to select one by name or by index.

import { toGeojsonContours } from "landxml";

const landXmlString = `<?xml version="1.0"?>...<LandXML>...</LandXML>`;

// By name
const byName = await toGeojsonContours(landXmlString, 2, true, "ExistingGround");

// By index (0-based)
const byIndex = await toGeojsonContours(landXmlString, 2, true, 1);

Reproject GeoJSON

reprojectGeoJson wraps mproj and works with both WKT strings (exported by Civil 3D when a drawing is geo-referenced) and standard proj4 definition strings.

import { reprojectGeoJson } from "landxml";

// wktString is available on every surface returned by toGeojsonContours / toGlbAndContours
const reprojected = reprojectGeoJson(
  geojson,
  wktString, // source CRS — WKT or proj4 string
  "WGS84", // target CRS (default)
  true, // keep original geometry as feature property "_rawGeometry"
);

API Reference

toGlbAndContours(landXmlString, contourInterval?, generateOutline?, center?, surfaceId?)

Parameter	Type	Default	Description
landXmlString	string	—	Raw LandXML XML string
contourInterval	number	2	Vertical interval between contour lines
generateOutline	boolean	true	Append surface boundary as a z=0 GeoJSON feature
center	"auto" | "origin" | [x, y]	"auto"	GLB model origin strategy
surfaceId	string | number	-1	Surface name or index; -1 returns all surfaces

Returns Promise<GlbAndContoursResult[]> where each element contains name, description, sourceFile, timeStamp, wktString, glb, center, download, and geojson.

toGeojsonContours(landXmlString, contourInterval?, generateOutline?, surfaceId?)

Parameter	Type	Default	Description
landXmlString	string	—	Raw LandXML XML string
contourInterval	number	2	Vertical interval between contour lines
generateOutline	boolean	true	Append surface boundary as a z=0 GeoJSON feature
surfaceId	string | number	-1	Surface name or index; -1 returns all surfaces

Returns Promise<{ name, description, sourceFile, timeStamp, wktString?, geojson }[]>.

toGlb(landXmlString, center?, surfaceId?)

Parameter	Type	Default	Description
landXmlString	string	—	Raw LandXML XML string
center	"auto" | "origin" | [x, y]	"auto"	GLB model origin strategy. 3D models are sensitive to large coordinates — "auto" offsets to the XY median
surfaceId	string | number	-1	Surface name or index; -1 returns all surfaces

Returns Promise<{ name, description, sourceFile, timeStamp, glb, center, download }[]>.

reprojectGeoJson(geojson, sourceProjection, targetProjection?, keepOriginalGeometry?)

Parameter	Type	Default	Description
geojson	FeatureCollection	—	GeoJSON to reproject
sourceProjection	string	—	Proj4 or WKT string of the source CRS
targetProjection	string	"WGS84"	Proj4 or WKT string of the target CRS
keepOriginalGeometry	boolean	true	Store original coordinates under feature.properties._rawGeometry

Returns the mutated FeatureCollection with updated coordinates.

Multi-surface center behaviour

When a LandXML file contains multiple surfaces and center is set to "auto" (the default), the package computes a single shared median center across all surfaces' points. Every GLB produced in that call is offset by the same origin, so the surfaces remain correctly positioned relative to each other in your 3D scene. This happens automatically — no extra configuration is needed.

If you need each surface to be individually centered (e.g. you are processing them in isolation), pass an explicit [x, y] pair instead.