Download Contour Lines as GeoJSON for QGIS & ArcGIS

What is GeoJSON Format?

GeoJSON is an open standard format designed for representing simple geographical features and their non-spatial attributes. Based on JavaScript Object Notation (JSON), GeoJSON has become the de facto standard for web mapping and is widely supported by modern GIS software.

For contour lines, GeoJSON stores each contour as a LineString or MultiLineString feature with properties including elevation value, making it ideal for spatial analysis and visualization. The format's simplicity and readability make it easy to integrate into various workflows.

Why Choose GeoJSON for Contour Lines?

• Universal Compatibility: Works seamlessly with QGIS, ArcGIS, MapBox, Leaflet, and virtually all modern GIS and web mapping tools
• Lightweight and Efficient: Compact file size with fast loading times, perfect for web applications
• Human-Readable: Text-based format that's easy to inspect, debug, and modify with any text editor
• Web-Native: Designed for web mapping, making it the best choice for online interactive maps
• Rich Metadata: Stores elevation values and other properties directly with each contour line
• No Projection Issues: Uses WGS84 (EPSG:4326) coordinate system by default, avoiding common projection problems

Software That Uses GeoJSON

Desktop GIS Software

• QGIS: Native support for importing and exporting GeoJSON layers
• ArcGIS Pro: Full GeoJSON support for analysis and visualization
• GRASS GIS: Can import GeoJSON through various modules
• Global Mapper: Reads and writes GeoJSON files

Web Mapping Libraries

• Leaflet: Direct GeoJSON layer support with L.geoJSON()
• MapBox GL JS: Native GeoJSON source integration
• OpenLayers: Comprehensive GeoJSON format support
• Google Maps API: Can render GeoJSON features

Data Processing Tools

• Python (GeoPandas, Fiona): Excellent GeoJSON support for analysis
• R (sf package): Read and write GeoJSON spatial data
• PostGIS: Can import GeoJSON into PostgreSQL databases
• GDAL/OGR: Convert GeoJSON to and from hundreds of other formats

How to Download Contour Lines as GeoJSON

1. Navigate to the Tool: Visit NZ Elevation Tools and use the interactive map to locate your area of interest
2. Draw Your Boundary: Click and drag to create a rectangle around the area you want contours for (up to 100 km²)
3. Set Contour Interval: Choose an appropriate interval:
   • 0.5-2m: Highly detailed terrain analysis, small urban areas
   • 5m: Standard topographic mapping, hiking trail planning
   • 10-20m: Regional overview maps, large area analysis
   • 20-50m: National-scale mapping, general terrain visualization
4. Select GeoJSON Format: Choose "GeoJSON" from the export format dropdown menu
5. Download: Click the download button to generate your contour lines. The GeoJSON file will be created from LINZ LiDAR data and downloaded instantly
6. Import to Your Software: Open the GeoJSON file in QGIS, ArcGIS, or your web mapping application

Using GeoJSON Contours in QGIS

QGIS makes it incredibly easy to work with GeoJSON contour files:

1. Import: Drag and drop the GeoJSON file into QGIS, or use Layer → Add Layer → Add Vector Layer
2. Styling: Right-click the layer → Properties → Symbology to customize line colors, widths, and labeling based on elevation values
3. Label Contours: Use the elevation property field to automatically label contour lines with their heights
4. Analysis: Perform spatial queries, create cross-sections, or combine with other spatial datasets
5. Export: Convert to other formats like Shapefile, KML, or DXF as needed

Common Use Cases for GeoJSON Contours

Web Mapping Applications

GeoJSON is the perfect choice for displaying contour lines on interactive web maps. Use Leaflet or MapBox to create engaging topographic visualizations for hiking websites, outdoor apps, or planning portals. The lightweight format ensures fast loading times even for detailed terrain.

Spatial Analysis in GIS

Import GeoJSON contours into QGIS or ArcGIS Pro for comprehensive terrain analysis. Calculate slopes, aspects, viewsheds, or watershed boundaries. Combine with other spatial layers like land parcels, infrastructure, or vegetation data for multi-layered analysis.

Trail Planning and Recreation

Use GeoJSON contours to plan hiking, biking, or running routes across New Zealand's diverse terrain. Identify elevation gain, locate ridgelines, and avoid steep sections. Perfect for planning adventures in regions like Fiordland, Tongariro, or the Southern Alps.

Environmental Studies

Researchers use GeoJSON contour data for habitat modeling, erosion analysis, and climate studies. The format's compatibility with Python and R makes it ideal for programmatic analysis and reproducible research workflows.

Urban Planning and Development

Planners and engineers use GeoJSON contours to assess building sites, design drainage systems, and evaluate development proposals. Import into GIS alongside zoning maps, utilities, and cadastral data for comprehensive site analysis.

Tips for Working with GeoJSON Contours

Optimize File Size

For large areas, consider using a larger contour interval (10-20m instead of 1-2m) to reduce file size while maintaining useful terrain information. You can also simplify geometries using QGIS or GDAL if needed for web mapping.

Coordinate System Awareness

GeoJSON uses WGS84 (EPSG:4326) by default. If you need to work in NZTM (EPSG:2193) for New Zealand projects, you can easily reproject in QGIS using Vector → Data Management Tools → Reproject Layer.

Combine with Other Data

GeoJSON contours work excellently alongside other spatial datasets. Overlay them with satellite imagery, aerial photos, or OpenStreetMap data to create comprehensive topographic maps. The format's web-native design makes these combinations seamless.

Programmatic Processing

Use Python with libraries like GeoPandas, Shapely, or Fiona to programmatically process GeoJSON contours. You can extract specific elevation ranges, calculate statistics, or combine multiple files into regional datasets.

GeoJSON vs Other Formats

GeoJSON vs Shapefile

While Shapefile is a traditional GIS format, GeoJSON offers several advantages: single file (vs multiple .shp, .dbf, .shx files), better attribute storage, web-native design, and no field name limitations. However, Shapefile may be better for very large datasets in some desktop GIS workflows.

GeoJSON vs DXF

DXF is designed for CAD software like AutoCAD, while GeoJSON is purpose-built for GIS and web mapping. Choose GeoJSON for spatial analysis and web applications, and DXF for architectural and engineering projects.

GeoJSON vs KML

KML is optimized for Google Earth and includes 3D visualization features. GeoJSON is better for GIS analysis and web mapping. If you need Google Earth compatibility, consider our KML export option.

About LINZ LiDAR Data

The contour lines you download are generated from Land Information New Zealand (LINZ) LiDAR elevation data. This professional-grade data provides exceptional accuracy with vertical precision typically within ±0.5 to 1 meter, depending on terrain and vegetation.

LINZ LiDAR coverage includes most populated areas and regions of interest across New Zealand, from Auckland to Invercargill, covering urban areas, national parks, and popular outdoor recreation zones. The data is continuously updated and improved, ensuring you have access to the most current elevation information.

Frequently Asked Questions

Is GeoJSON the best format for QGIS?

Yes, QGIS has excellent native GeoJSON support. It's often preferable to Shapefile because it's a single file, has no field name length restrictions, and handles complex geometries better. For large datasets, consider GeoPackage as an alternative.

Can I edit GeoJSON files?

Absolutely! GeoJSON is text-based, so you can open it in any text editor. However, for spatial editing, use QGIS or ArcGIS to maintain geometry validity. You can also edit programmatically with Python or JavaScript.

What coordinate system does the GeoJSON use?

Our GeoJSON files use WGS84 (EPSG:4326), the standard for web mapping. If you need NZTM (EPSG:2193) for New Zealand-specific projects, you can easily reproject in QGIS or ArcGIS.

How large are the GeoJSON files?

File size depends on your selected area and contour interval. A typical 10 km² area with 5m contours will be 2-5 MB. For web use, consider larger intervals or simplifying geometries to reduce file size.

Can I use this data commercially?

Yes! The LINZ LiDAR data is licensed under CC BY 4.0, allowing commercial use with appropriate attribution to LINZ.

Does GeoJSON work with ArcGIS Online?

Yes, ArcGIS Online can import GeoJSON files. You can upload them as hosted feature layers or add them directly to web maps.

Related Resources

Explore our other format-specific guides for different use cases:

• Download Contours as DXF - For AutoCAD and CAD software
• Download Contours as PDF - For printing topographic maps
• Download Contours as KML - For Google Earth visualization
• Download Contours as SVG - For graphic design and web use
• Create Elevation Profiles - Generate trail elevation profiles