Mapzen

Mapzen's terrain tiles are a global DEM dataset, including bathymetry. The dataset is an assimilation of multiple open datasets.

Coverage and resolution

Data is provided at a 1 arc-second resolution, corresponding to a resolution of about 30m at the equator. However, parts of the dataset are interpolated from lower-resolution datasets. The resolution of the source datasets is shown below:

Mapzen source datasets.
Resolution of Mapzen source datasets. Source: github.com/tilezen/joerd.

Adding Mapzen to Open Topo Data

Make a new folder for the dataset:

mkdir ./data/mapzen

Download the tiles from AWS. I found it easiest to use the aws cli:

aws s3 cp --no-sign-request --recursive s3://elevation-tiles-prod/skadi ./data/mapzen

Extract all the .hgt files. Create a config.yaml file:

datasets:
- name: mapzen
  path: data/mapzen/

Rebuild to enable the new dataset at localhost:5000/v1/mapzen.

make build && make run

Extra performance

.hgt files are extremely large. You'll get a large space reduction with little read penalty by converting to a compressed geotiff:

bash gdal_translate -co COMPRESS=DEFLATE -co PREDICTOR=2 {hgt_filename} {tif_filename}

Public API

The Open Topo Data public API lets you query the Mapzen dataset for free:

curl https://api.opentopodata.org/v1/mapzen?locations=57.688709,11.976404
{
  "results": [
    {
      "elevation": 55.0, 
      "location": {
        "lat": 57.688709, 
        "lng": 11.976404
      }
    }
  ], 
  "status": "OK"
}

The public API uses Version 1.1 of Mapzen, downloaded from AWS on May 2020