Dataset

Overview

The GPXZ elevation dataset is a composite dataset made by combining multiple open sources of elevation data.

Our dataset covers the entire globe:

Terrain (bare earth) elevation is given globally.
Land elevation uses high-resolution terrain lidar data with a resolution down to 50cm. Where lidar isn't available, the 30m Copernicus DEM is used, post-processed to reduce forest and building bias.
Ice-surface elevation is given at the poles.
Bathymetry (depth below sea level) is included in the dataset. Most GPXZ API endpoints have an option to remove bathymetry and return an elevation of 0 for locations at sea.

The current version of the GPXZ dataset is 2025.1.

While high-resolution lidar coverage for your country of interest may look patchy, these source datasets usually prioritise areas where people live and which researchers study.
Resolution is given in metres and represents horizontal precision. A 30m dataset will be unable to capture topographic features smaller than 30m.

0.5m → 2m

5m → 10m

30m

110m

450m

The GPXZ dataset is made by layering open elevation sources.

For sources that have a non-bathymetric elevation values over ocean areas (either sea-surface height or dummy values), this is removed.
Sources are normalised to a common vertical datum (EGM2008).
Small holes are filled using kriging. (Large holes will be filled during merging).
Source-specific preprocessing is done to remove areas of corruption and noise.
GPXZ uses bare-earth terrain data (DTMs) for hires coverage. Areas without hires coverage use Copernicus surface data (DSMs), processed to remove vegetation and structures.

Land source rasters are merged using the algorithm described in Petrasova et al (2017). A max merge angle of 2° is used.

The merged land elevation raster is then merged with bathymetry.
The algorithm used to merge the land data leaves a zone of intermediary-quality inside the edge of the hi-res raster. This would be a problem bathymetry merging as these datasets are often low resolution, and coastal data is important for many end users.
Instead, an estimated elevation profile is linearly interpolated from the edge of the land data out to a distance of 1km offshore. Next, a distance-weighted blend is made between this estimated elevation profile and the bathymetry data.
As a result, the land data is unchanged during this process, preserving the accuracy of the coastline.

API responses will have the value 2025.1 in the X-DATASET-VERSION header.
Rasters will have the value 2025.1 in the GPXZ_DATASET_VERSION meta tag.
The /v1/elevation/sources endpoint will return some new sources, and some old sources will be removed.

New Zealand (most of the country including all major population centres are now covered at 1m).
USA (most of the country is now covered at 1m).
Canada (expanded 1m lidar coverage, particularly in Quebec and Ontario).
France (filled some departments of missing data at 1m)

USA (both 1m and 10m datasets updated to the latest version)
England (updated to the latest version)
GEBCO (wordwide) and EMOD (Europe) bathymetry have been updated to their latest versions.

v2025.1 uses a new gobal basemap for areas without lidar coverage. We used a variety of data sources and satistical methods to reduce the tree and building bias in the 30m Copernicus surface dataset. As a result, the GPXZ elevation dataset is now a global terrain model.
All elevation values are now given relative to EGM2008 (EPSG:3855).

Smoother land-bathymetry mergeing.
Smoother merging between datasets.
Improved interpolation algorith, resolving linear artefacts in hole interpolation.
Expaned automated QA process identifying and resolving more errors contained in source DEMs.
Manual fixing of customer-identified areas of source data inaccuracies.