aixm-parser

First JavaScript/TypeScript parser for AIXM 5.1.1 (Aeronautical Information Exchange Model) with geodesic geometry, temporal model, and GeoJSON output.

Features

• Streaming parsing of large AIXM files (SAX + DOM hybrid)
• 30 typed feature interfaces (airports, airspaces, navaids, routes, obstacles, services)
• GML to GeoJSON conversion with geodesic accuracy on WGS84
• Temporal model (BASELINE / PERMDELTA / TEMPDELTA / SNAPSHOT merging)
• Cross-reference resolution (xlink:href, circular detection, reverse lookup)
• Elevation support (aixm:elevation emitted as third GeoJSON coordinate, meters)
• CLI: aixm-to-geojson input.xml output.geojson
• Dual ESM/CJS build, TypeScript-first

Install

npm install aixm-parser

Quick Start

import { parse } from 'aixm-parser';
import { readFileSync } from 'fs';

const xml = readFileSync('Donlon.xml', 'utf-8');
const result = await parse(xml);

// High-level accessors
const airports = result.airports();
const airspaces = result.airspaces();
const navaids = result.navaids();

console.log(`${airports.length} airports, ${airspaces.length} airspaces, ${navaids.length} navaids`);

// Access typed properties
for (const apt of airports) {
  console.log(apt.properties.name, apt.properties.locationIndicatorICAO);
}

CLI

npm install -g aixm-parser   # or: npx -p aixm-parser aixm-to-geojson ...

aixm-to-geojson input.xml output.geojson
aixm-to-geojson input.xml --pretty > out.geojson
aixm-to-geojson input.xml output.geojson --stats --tolerance 50

Options: --keep-null (keep features without geometry), --tolerance <m> (densification, default 100), --pretty, --stats.

GeoJSON Output

// Convert all features to a GeoJSON FeatureCollection
const geojson = result.toGeoJSON();

// Skip features without geometry (e.g. organisations, frequencies)
const spatial = result.toGeoJSON({ skipNullGeometry: true });

// Or convert individual features
import { featureToGeoJSON, extractGeometry } from 'aixm-parser';

const feature = result.features[0];
const geoFeature = featureToGeoJSON(feature);
const geometry = extractGeometry(feature.xmlChunk);

Supported GML geometry types:

• gml:Point / aixm:ElevatedPoint (elevation as third coordinate)
• gml:CircleByCenterPoint (densified on WGS84 ellipsoid)
• gml:ArcByCenterPoint (geodesic arc via Karney algorithm)
• gml:GeodesicString / gml:Geodesic (great circle segments)
• gml:Curve / aixm:ElevatedCurve (compound curves with multiple segments)
• gml:PolygonPatch with exterior/interior rings
• aixm:Surface / aixm:ElevatedSurface

result.toGeoJSON() additionally:

• resolves arc/circle centers given as <gml:pointProperty xlink:href="#id"/> across the whole document
• assembles geometry for Route features from their RouteSegment LineStrings (MultiLineString)

Temporal Model

AIXM features change over time through TimeSlices. Query the state at any point in time:

// Get feature state at a specific timestamp
const state = result.featureAt('uuid.abc-123', new Date('2024-06-01'));
console.log(state.properties.name); // merged from BASELINE + deltas
console.log(state.activeTemporalOverlays); // number of active TEMPDELTAs

// Low-level: compute state from a raw feature
import { computeState, getTimeline } from 'aixm-parser';

const timeline = getTimeline(rawFeature); // all states in chronological order
const current = computeState(rawFeature, new Date());

Cross-References

AIXM features reference each other via xlink:href. The built-in registry resolves them:

const { registry } = await parse(xml);

// Resolve a single reference
const airport = registry.resolve('urn:uuid:abc-123');
const navaid = registry.resolve('#NAV_DON');

// Resolve all pending references
const resolved = registry.resolveAll();
const unresolved = resolved.filter(r => !r.target);

// Reverse lookup: who references this feature?
const referencing = registry.getReferencingFeatures('uuid-of-airport');

// Build the full reference graph
const graph = registry.buildGraph();

// Detect circular references
const cycles = registry.detectCircularRefs();

Geodesic Geometry

Arc and circle geometry is computed on the WGS84 ellipsoid using the Karney algorithm:

import { densifyArcByCenterPoint, densifyCircle, geodesicDistance } from 'aixm-parser';

// Arc from 090 to 270 degrees clockwise, radius 5km
const arc = densifyArcByCenterPoint(
  { lon: -1.0, lat: 51.0 }, 5000, 90, 270, true, 100
);

// Circle with 15 NM radius
const circle = densifyCircle(
  { lon: -22.1, lat: 52.37 }, 15 * 1852, 100
);

// Distance between two points
const dist = geodesicDistance(
  { lon: -0.1278, lat: 51.5074 },  // London
  { lon: 2.3522, lat: 48.8566 }    // Paris
);

Typed Features

30 AIXM feature types with TypeScript interfaces:

API Reference

parse(xml, options?)

Main entry point. Returns a ParseResult with:

Options

interface ParseOptions {
  errorMode?: 'strict' | 'lenient'; // default: 'lenient'
}

interface GmlToGeoJSONOptions {
  toleranceMeters?: number;    // densification tolerance, default: 100
  skipNullGeometry?: boolean;  // omit features without geometry
  pointResolver?: (gmlId: string) => Position | null; // custom center resolver
}

Requirements

• Node.js >= 20.0.0
• TypeScript >= 5.0 (for type definitions)

License

MIT