Download DEM Data NZ: A Complete Guide to New Zealand Digital Elevation Models

What Is a Digital Elevation Model (DEM)?

A digital elevation model, commonly known as a DEM, is a three-dimensional representation of the Earth's surface stored as a regular grid of elevation values. Each cell in the grid holds a single elevation measurement, and together the cells form a raster dataset that describes the height of the terrain across an area. DEMs are one of the most fundamental datasets in geographic information science, underpinning everything from flood modelling and viewshed analysis to slope calculations and contour line generation.

In practical terms, a DEM is a file where every pixel represents a geographic location and its associated height above a reference datum. If you open a DEM in GIS software such as QGIS or ArcGIS, you see a greyscale image where brighter pixels represent higher elevations and darker pixels represent lower elevations. The resolution of a DEM refers to the size of each pixel on the ground. A 1-metre resolution DEM means each pixel covers a one-metre-by-one-metre area, while a 30-metre resolution DEM means each pixel covers a 30-metre-by-30-metre area.

DEMs are typically stored in raster formats such as GeoTIFF, Cloud Optimised GeoTIFF (COG), or ESRI Grid. The GeoTIFF format is the most common for New Zealand elevation data, as it embeds geographic coordinate system information directly in the file header, allowing GIS software to place the data correctly on a map without separate georeferencing.

DEM vs DSM vs DTM: Understanding the Differences

The terms DEM, DSM, and DTM are often used interchangeably, but they refer to different types of elevation data with important distinctions. Understanding these differences is essential when choosing the right dataset for your project.

Digital Surface Model (DSM)

A digital surface model captures the elevation of the highest surface at each point, including buildings, trees, power lines, and any other features above the bare ground. A DSM of a forested hillside shows the elevation of the tree canopy, not the ground beneath it. DSMs are useful for telecommunications planning, line-of-sight analysis, urban modelling, and any application where the height of objects above ground matters.

Digital Terrain Model (DTM)

A digital terrain model represents the bare-earth surface with all vegetation, buildings, and other above-ground features removed. A DTM of the same forested hillside shows the actual ground elevation beneath the trees. DTMs are the preferred dataset for hydrological modelling, slope analysis, contour generation, earthworks calculations, and most terrain analysis tasks. Creating a DTM from LiDAR data requires classifying ground returns and filtering out non-ground points, a process that LINZ applies to its LiDAR datasets before publishing.

DEM as a Generic Term

The term digital elevation model is sometimes used as a generic umbrella that encompasses both DSMs and DTMs. In other contexts, DEM refers specifically to a bare-earth model equivalent to a DTM. When downloading DEM data from LINZ, the dataset descriptions clearly state whether the data is a DSM or a DTM, so always check the metadata to confirm you are getting the right type for your needs. For most applications including contour generation, elevation profiling, and slope analysis, you want the DTM (bare-earth) product.

New Zealand DEM Data Sources

Several sources provide digital elevation model data covering New Zealand, ranging from high-resolution LiDAR-derived products to global satellite-based datasets. The choice of source depends on the resolution, accuracy, and coverage you need for your project.

LINZ LiDAR DEMs (Highest Resolution)

Land Information New Zealand (LINZ) coordinates the national LiDAR programme, which has captured high-resolution elevation data across much of the country over the past decade. LiDAR-derived DEMs from LINZ are available at resolutions of 1 metre or finer, making them the most detailed elevation data available for New Zealand. These datasets are published as both DTM and DSM products, with vertical accuracy typically in the range of plus or minus 0.1 to 0.2 metres for open terrain.

LINZ LiDAR DEMs are distributed as Cloud Optimised GeoTIFF (COG) files through the LINZ Data Service. Coverage is regional rather than nationwide in a single seamless product, meaning you may need to download multiple tiles or datasets to cover your area of interest. Major coverage areas include Canterbury, Wellington, Hawke's Bay, Bay of Plenty, Waikato, Otago, and many other regions. New surveys are continuously being added. For a comprehensive overview of LiDAR coverage and technology, see our LiDAR data New Zealand guide.

NZ 8m DEM

The NZ 8m DEM is a nationwide digital elevation model with an 8-metre pixel resolution. It was created by interpolating elevation data from the Topo50 contour lines and spot heights maintained by LINZ. While it does not match the accuracy or detail of LiDAR-derived DEMs, the NZ 8m DEM provides seamless national coverage, making it useful for regional and national-scale analyses where high resolution is not critical. It is freely available from the LINZ Data Service.

SRTM 30m DEM

The Shuttle Radar Topography Mission (SRTM) collected elevation data across most of the Earth's surface in February 2000 using radar interferometry from the Space Shuttle Endeavour. The SRTM DEM is available at approximately 30-metre resolution for New Zealand and can be downloaded from NASA's EarthData or the USGS Earth Explorer platform. SRTM data is a DSM rather than a DTM, meaning it includes the height of vegetation and structures. It is useful as a free, globally consistent baseline dataset but lacks the precision needed for detailed engineering or hydrological work.

ASTER GDEM 30m

The Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM (ASTER GDEM) provides global coverage at approximately 30-metre resolution, similar to SRTM. Produced from optical stereo imagery collected by the ASTER instrument aboard NASA's Terra satellite, the ASTER GDEM covers areas beyond SRTM's latitude limits. However, for New Zealand, SRTM generally provides better quality than ASTER due to New Zealand's persistent cloud cover affecting optical imagery. ASTER GDEM is available from NASA's EarthData portal.

How to Download Raw DEM Data from LINZ

The LINZ Data Service (LDS) is the primary portal for accessing New Zealand's digital elevation model data. Downloading raw DEM data requires several steps and some familiarity with geospatial data formats and coordinate systems.

1. Visit the LINZ Data Service: Go to data.linz.govt.nz and create a free account if you do not already have one. An account is required to download data.
2. Search for DEM Datasets: Use the search bar to find elevation datasets. Search terms like "DEM", "LiDAR", "elevation", or specific region names (e.g., "Canterbury LiDAR 1m DEM") will return relevant results. Browse the elevation data category to see all available datasets.
3. Choose Your Dataset: Select the DEM that matches your area and resolution requirements. Check the metadata to confirm whether it is a DTM or DSM, the resolution, the coordinate reference system, and the date of capture. Regional LiDAR DEMs at 1-metre resolution offer the best detail, while the NZ 8m DEM provides nationwide coverage.
4. Select Your Area of Interest: Use the map interface to draw a bounding box or polygon around your area of interest. For large datasets, this limits the download to only the tiles you need rather than the entire dataset.
5. Choose the Download Format: Select GeoTIFF or Cloud Optimised GeoTIFF (COG) as the output format. GeoTIFF is universally supported by GIS software. COG files are optimised for cloud-based access and streaming but work equally well as local files.
6. Select the Coordinate System: Choose a coordinate reference system for the output. Common choices for New Zealand include NZGD2000 / New Zealand Transverse Mercator 2000 (EPSG:2193) for projected coordinates in metres, or NZGD2000 geographic coordinates (EPSG:4167) for latitude and longitude. The vertical datum is typically NZVD2016 (New Zealand Vertical Datum 2016).
7. Download the Data: Request the export and wait for the LINZ Data Service to prepare your files. Large datasets may take several minutes to process. You will receive an email with a download link when the export is ready.

While this process gives you access to the raw elevation data, it requires GIS expertise to work with the resulting files. If you need processed outputs like contour lines, elevation profiles, or enriched coordinate files, NZ Elevation Tools provides a much faster path.

Working with DEM Files

Once you have downloaded raw DEM data from LINZ, you need appropriate software and knowledge to open, process, and analyse the files. This section covers the key technical considerations.

GeoTIFF Format

GeoTIFF is the standard file format for DEM data in New Zealand. A GeoTIFF file is essentially a TIFF image with embedded geospatial metadata, including the coordinate reference system, the geographic extent (bounding box), and the pixel size. Each pixel stores a floating-point elevation value rather than a colour. GeoTIFF files can be very large, especially for high-resolution LiDAR DEMs. A 1-metre resolution DEM covering a 10-kilometre-by-10-kilometre area contains 100 million pixels, resulting in file sizes of several hundred megabytes.

Coordinate Systems

New Zealand DEM data uses specific coordinate reference systems that you need to understand when working with the files. The horizontal coordinate system is typically NZGD2000 / New Zealand Transverse Mercator 2000 (NZTM2000, EPSG:2193), which expresses positions in eastings and northings measured in metres. Some datasets may use NZGD2000 geographic coordinates (EPSG:4167), which express positions in latitude and longitude degrees. The vertical datum for modern LINZ elevation data is NZVD2016, which defines the zero-elevation reference surface for height measurements across New Zealand.

Software Required

Working with raw DEM data requires GIS or geospatial processing software. Common options include:

• QGIS: A free, open-source GIS application that can open GeoTIFF files, visualise elevation data, generate contour lines, create hillshade renderings, and perform terrain analysis. QGIS is powerful but has a steep learning curve for new users.
• GDAL: The Geospatial Data Abstraction Library is a command-line toolkit for translating, processing, and analysing raster and vector geospatial data. GDAL commands like gdalinfo, gdalwarp, and gdal_contour are essential tools for working with DEM files, but they require comfort with the command line.
• ArcGIS Pro: Esri's commercial GIS platform provides comprehensive DEM analysis tools including surface analysis, 3D visualisation, and spatial modelling. ArcGIS requires a paid licence.
• Global Mapper: A commercial GIS tool known for excellent raster handling and terrain analysis capabilities, including direct import of many DEM formats and easy contour generation.

For users who do not have GIS software or the time to learn these tools, NZ Elevation Tools provides the same derived outputs, such as contour lines and elevation profiles, through a simple web interface with no installation or technical expertise required.

The Easy Alternative: NZ Elevation Tools

Downloading and processing raw DEM data is powerful but time-consuming. You need to create a LINZ account, find the right dataset, choose coordinate systems, wait for exports to process, download large files, install GIS software, and learn how to use it before you can extract the information you actually need. For many users, this workflow is far more complex than the task requires.

NZ Elevation Tools provides the most commonly needed outputs derived from DEM data through a simple web interface. The tool processes LINZ LiDAR elevation data behind the scenes and delivers results in seconds. No account registration, no software installation, and no GIS expertise needed.

Contour Lines from DEM Data

One of the most common reasons people download DEM data is to generate contour lines. NZ Elevation Tools lets you draw a rectangle on the map, choose a contour interval from 0.5 to 50 metres, and download contour lines in your preferred format. Export as GeoJSON for GIS, DXF for CAD, PDF for printing, or several other formats. Learn more in our contour lines New Zealand guide.

Elevation Profiles from DEM Data

Elevation profiles show how the terrain rises and falls along a route or transect. Instead of loading a DEM into GIS software and manually extracting profile data, use NZ Elevation Tools to upload a GPX, KML, or GeoJSON route file and get an interactive elevation chart instantly. This is invaluable for planning hiking trails, cycling routes, or pipeline alignments. See our elevation profile generator guide for details.

File Enrichment with Elevation Data

If you have a file containing geographic coordinates but no elevation values, NZ Elevation Tools can add accurate elevation data to every point. Upload a CSV file with latitude and longitude columns, or a GPX, KML, or GeoJSON file, and download the enriched version with elevation values added from LINZ LiDAR data. This replaces the manual workflow of loading both your coordinates and a DEM into GIS software and performing a point sampling operation.

No GIS Required

The entire process runs in your web browser. There is nothing to install, no files to manage locally, and no need to understand coordinate reference systems, GeoTIFF headers, or raster processing pipelines. You interact with an intuitive map interface and receive your results as a clean download ready for immediate use.

Common Uses for DEM Data

Digital elevation models are among the most versatile datasets in geospatial science. Here are the most common applications for DEM data in New Zealand.

Flood Modelling and Hazard Assessment

High-resolution DEMs are essential for simulating flood events, delineating floodplains, and assessing the risk of inundation for specific properties and infrastructure. Regional councils throughout New Zealand use LiDAR-derived DEMs to model river flooding, coastal storm surge, and tsunami inundation scenarios. The 1-metre resolution of LINZ LiDAR DEMs enables accurate identification of flow paths, storage areas, and flood extents at the individual property level.

Viewshed and Line-of-Sight Analysis

Viewshed analysis uses a DEM to determine which areas of the landscape are visible from a given observation point. This is used for telecommunications tower placement, wind farm visual impact assessment, landscape architecture, property development, and military applications. A DSM (which includes vegetation and buildings) is typically preferred over a DTM for viewshed analysis, as above-ground features block lines of sight.

Slope and Aspect Calculation

DEMs allow the calculation of slope (steepness) and aspect (the direction a slope faces) for every point in the landscape. Slope data is critical for erosion modelling, landslide susceptibility mapping, agricultural land classification, and building site assessment. Aspect data is important for solar energy potential analysis, snow accumulation modelling, and understanding microclimates that affect vegetation patterns.

Cut-and-Fill Volume Calculations

Engineers and developers use DEMs to calculate the volume of earth that needs to be cut from high points and filled into low points to create a level building platform or road alignment. Comparing a pre-construction DEM with a design surface produces accurate cut-and-fill volumes for cost estimation and resource planning. This is a standard workflow in civil engineering and land development projects across New Zealand.

Drainage and Catchment Planning

DEMs enable the delineation of catchment boundaries, the identification of natural drainage paths, and the design of stormwater management systems. By analysing the flow direction and flow accumulation derived from a DEM, hydrologists can map stream networks, identify areas prone to ponding, and design effective drainage infrastructure. This is critical for subdivision design, farm planning, and environmental management.

Data Resolution Comparison

The following table compares the main DEM data sources available for New Zealand, helping you choose the right dataset for your requirements.

For most applications in New Zealand, the LINZ LiDAR DEM provides the best combination of resolution and accuracy. The NZ 8m DEM is a practical fallback for areas without LiDAR coverage or for regional-scale analyses where 1-metre resolution is unnecessary. SRTM and ASTER are useful for broad-scale comparisons or as supplementary datasets, but their coarser resolution and lower accuracy limit their utility for detailed work.

Data Licensing and Attribution

LINZ elevation data, including all LiDAR-derived DEMs and the NZ 8m DEM, is released under the Creative Commons Attribution 4.0 International licence (CC BY 4.0). This licence allows you to copy, redistribute, adapt, and build upon the data for any purpose, including commercial use, provided you give appropriate credit to the data source.

The standard attribution for LINZ elevation data is: "Sourced from the LINZ Data Service and licensed for reuse under the CC BY 4.0 licence." When using DEM data in publications, reports, or applications, include this attribution alongside your work. NZ Elevation Tools includes LINZ attribution automatically in all generated outputs.

SRTM data is in the public domain and does not require attribution, though crediting NASA is good practice. ASTER GDEM data is jointly produced by NASA and Japan's Ministry of Economy, Trade and Industry (METI) and is freely available for use with appropriate citation.

Frequently Asked Questions

What is the best DEM data source for New Zealand?

For the highest quality and resolution, use the LINZ LiDAR DEMs at 1-metre resolution. These are available free of charge through the LINZ Data Service and cover most populated and environmentally significant areas of New Zealand. For areas without LiDAR coverage, the NZ 8m DEM provides seamless nationwide coverage at a lower resolution.

Do I need GIS software to use DEM data?

If you download raw DEM files (GeoTIFF format), yes, you need GIS software such as QGIS, ArcGIS, or Global Mapper to open, visualise, and analyse the data. However, NZ Elevation Tools processes DEM data for you and delivers the results through a web browser, so you can obtain contour lines, elevation profiles, and enriched coordinate files without any GIS software.

What format should I download DEM data in?

GeoTIFF is the most widely supported format and the best default choice for DEM data. Cloud Optimised GeoTIFF (COG) is a newer variant that supports efficient streaming and partial reads, making it ideal for cloud-based workflows and large datasets. Both formats are supported by all major GIS software platforms.

How do I generate contour lines from a DEM?

In GIS software, you can use the contour generation tool (e.g., GDAL's gdal_contour command or QGIS's "Contour" processing algorithm) to extract contour lines at your desired interval from a DEM raster. Alternatively, NZ Elevation Tools does this automatically. Simply select your area on the map, choose a contour interval, and download the contour lines in GeoJSON, DXF, PDF, or other formats.

What coordinate system does New Zealand DEM data use?

Most LINZ DEM data uses the NZGD2000 / New Zealand Transverse Mercator 2000 (NZTM2000) projected coordinate system, identified by EPSG code 2193. This system uses metres as its unit of measurement and is the standard for mapping and surveying in New Zealand. The vertical datum is NZVD2016, which defines the reference surface for elevation measurements. When working with DEM data in GIS software, ensure your project uses the same coordinate system to avoid misalignment.

Is New Zealand DEM data free to use?

Yes. All LINZ elevation data, including LiDAR DEMs and the NZ 8m DEM, is freely available under the CC BY 4.0 licence. You can use the data for personal, educational, and commercial purposes at no cost, provided you include the required attribution. NZ Elevation Tools is also completely free to use.

Related Resources

Explore our other guides for more detailed information on specific elevation data topics and tools for New Zealand:

• LiDAR Data New Zealand - Comprehensive guide to LiDAR technology, coverage, and data access in New Zealand
• Contour Lines New Zealand - Understanding and downloading contour line data for any area
• Topographic Maps NZ - Guide to New Zealand topo maps, from Topo50 to custom LiDAR-based maps
• Download Contours as GeoJSON - Export contour data for QGIS and GIS workflows
• Download Contours as DXF - Get contour data for AutoCAD and CAD applications
• Elevation Profile Generator - Create elevation charts from GPX, KML, and GeoJSON routes
• Add Elevation to CSV Files - Enrich spreadsheet data with accurate elevation values