Add Elevation Data to GeoJSON Files

Why Add Elevation to GeoJSON Files?

GeoJSON is the standard format for geographic data on the web. Adding elevation data (converting 2D coordinates to 3D) unlocks powerful visualization and analysis capabilities:

• 3D Web Maps: Create stunning 3D visualizations with Mapbox GL, Cesium, or deck.gl
• Elevation Profiles: Calculate and display elevation charts for routes and paths
• Terrain Analysis: Compute slope, aspect, and gradient for features
• Realistic Rendering: Enable terrain-following paths and height-based styling
• Complete Data: Ensure all coordinate arrays have [longitude, latitude, elevation] format

Perfect for Web Mapping Projects

GeoJSON with elevation data is essential for modern web mapping applications. Use enriched GeoJSON with:

• Leaflet: Display elevation tooltips and create elevation-colored layers
• Mapbox GL: Enable 3D terrain extrusion and elevation-based styling
• OpenLayers: Render features with accurate 3D positioning
• deck.gl: Create advanced 3D visualizations and animations
• Cesium: Build immersive 3D globe applications

How It Works

1. Upload: Drag and drop your GeoJSON file into the tool
2. Coordinate Detection: The tool identifies all coordinate arrays in Points, LineStrings, Polygons, and MultiGeometries
3. Elevation Lookup: Each coordinate pair is matched with precise LiDAR elevation data
4. Enhancement: Coordinates are converted from [lon, lat] to [lon, lat, elevation]
5. Download: Get your enhanced GeoJSON file ready for web mapping

GeoJSON Geometry Support

NZ Elevation Tools adds elevation data to all GeoJSON geometry types:

• Point: Single coordinate with elevation
• LineString: Array of coordinates forming a path
• Polygon: Closed rings with elevation-aware boundaries
• MultiPoint: Multiple independent points
• MultiLineString: Multiple separate paths
• MultiPolygon: Multiple separate polygons
• GeometryCollection: Mixed geometry types

Feature properties are preserved, and FeatureCollections are fully supported.

Use Cases

Interactive Trail Maps

Build interactive web maps of New Zealand hiking trails with elevation data. Display real-time elevation profiles as users hover over trail segments, color-code paths by steepness, and show 3D terrain views.

Property and Cadastral Mapping

Enhance property boundary GeoJSON data with elevation information for web-based land information systems, council planning portals, and real estate platforms.

Environmental Monitoring

Create elevation-aware visualizations of monitoring sites, conservation areas, waterways, and ecological zones. Perfect for DOC, regional councils, and environmental consultants.

Tourism Web Applications

Build engaging tourism web apps that showcase New Zealand's dramatic topography. Display mountain peaks, valleys, coastlines, and scenic routes with accurate 3D elevation.

GIS Analysis and Research

Use enriched GeoJSON for spatial analysis in web-based GIS platforms, research dashboards, and data visualization projects. Compatible with QGIS, ArcGIS Online, and other GIS tools.

Integration Examples

Mapbox GL with Elevation

Once you've enriched your GeoJSON with elevation data, you can use Mapbox GL's fill-extrusion layer to create stunning 3D visualizations. The elevation values enable realistic terrain-following paths and height-based feature styling.

Leaflet Elevation Profiles

Combine enriched GeoJSON with Leaflet.Elevation plugin to automatically generate interactive elevation charts for hiking trails, cycling routes, and scenic drives across New Zealand.

Custom Web Applications

Parse the elevation data in your JavaScript code to calculate total elevation gain/loss, identify steep sections, compute gradient percentages, and create custom terrain analysis tools.

Data Quality and Coverage

All elevation data comes from LINZ LiDAR surveys with typical vertical accuracy of ±0.5 to 1 meter. Coverage includes most populated areas of New Zealand, major conservation lands, and popular outdoor recreation areas.

The LiDAR data represents ground elevation (Digital Terrain Model), automatically filtering out buildings, vegetation, and other above-ground features.

File Format Notes

• GeoJSON files must use WGS84 coordinate system (EPSG:4326)
• Coordinates should be in [longitude, latitude] order (GeoJSON standard)
• Output coordinates will be [longitude, latitude, elevation] in meters
• File size limits apply - very large GeoJSON files may need to be split
• All feature properties and metadata are preserved

Frequently Asked Questions

What coordinate system does GeoJSON use?

GeoJSON uses WGS84 (EPSG:4326) by default, with coordinates in [longitude, latitude] order. After enrichment, coordinates become [longitude, latitude, elevation] where elevation is in meters above sea level.

Will adding elevation break my existing code?

Most mapping libraries handle both 2D and 3D coordinates seamlessly. The additional elevation value is typically ignored if not used, making enriched GeoJSON backward-compatible with 2D mapping code.

Can I add elevation to very large GeoJSON files?

Yes, but processing time increases with file size. For very large datasets, consider splitting into smaller regions or simplifying geometry before enrichment.

Is the elevation data accurate enough for engineering?

LINZ LiDAR data has sub-meter vertical accuracy, suitable for many planning and design purposes. For critical engineering applications, verify with on-site surveys.