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Base Guide

The base theme includes land, water, and other natural features. The theme also includes infrastructure features. The majority of these features come from OpenStreetMap, translated into the Overture schema. We often refer to the base theme as "everything else" you might need to make a complete map.

Some of our schema design choices include:

  • basic classification of features into type, subtype and class where appropriate.
  • parsing and normalization of common OSM tags, such as height and ele.
  • extraction of consistent OSM tags, such as wikidata to top-level properties.
  • direct pass-through of remaining relevant OSM tags.

In this guide​

This overview covers the feature types, dataset construction, and access for the base theme. A dedicated page covers one feature type in more depth:

  • Infrastructure: Transit features such as bus stops, platforms, and stations — including how they relate to the places and transportation themes — and entities like mountains that appear in both base and places by design, with example queries.

Dataset description​

Feature type descriptions​

There are six feature types in the base theme:

Bathymetry​

Bathymetry features provide topographic representations of underwater areas, such as parts of lake beds or ocean floors. The geometries are derived vectorized bathymetric data products from ETOPO1 and GLOBathy data.

Infrastructure​

Infrastructure features provide basic information about real-world infrastructure entities such as bridges, airports, runways, aerialways, communication towers, and power lines. All of the features are pulled from OpenStreetMap and converted to the Overture schema. See the infrastructure page for a closer look at transit features and how the infrastructure type relates to other themes.

Land​

Land features are representations of physical land surfaces. In Overture data releases, land features are sourced from OpenStreetMap. Global land derived from the inverse of OSM Coastlines. Translates natural tags from OpenStreetMap.

Land cover​

Land cover features indicate the primary natural or artificial surface material covering a land area on the earth, including vegetation types like forests and crops, built environments like cities, and natural surfaces like wetlands or barren ground. Overture's land cover data is derived from ESA WorldCover, high-resolution optical Earth observation data. Land cover features relate to Land use features in the following way: land cover is the physical thing covering the land, while land use is the human use to which the land is being put.

Land use​

Land use features specify the predominant human use of an area of land, for example commercial activity, recreation, farming, housing, education, or military use. Overture's land use data is a translation of the landuse tag from OpenStreetMap.

Water​

Water features represent ocean and inland water bodies. In Overture data releases, water features are sourced from OpenStreetMap. There are two main categories of water feature: ocean and inland water bodies — physical representations of inland and ocean marine surfaces, translating natural and waterway tags from OpenStreetMap.

Column definitions​

The column definitions for every type in the base theme are generated from the schema and live in the schema reference:

Sources and licensing​

Most base features — land, water, and infrastructure — come from OpenStreetMap and are translated into the Overture schema. The remaining feature types are drawn from dedicated global products: bathymetry from ETOPO1 and GLOBathy, and land cover from ESA WorldCover. Because it includes OpenStreetMap data, the base theme is published under the ODbL license. See the licensing and attribution page for more information.

How we build the dataset​

Base is a single-source, pass-through theme: each feature type is drawn from one source and translated into the Overture schema. There is no matcher and no conflation process.

Filtering. Non-bathymetry base features are produced through tag-based filtering of OpenStreetMap: relevant OSM tags are selected, normalized, and translated into the Overture schema, with remaining relevant tags passed through directly.

Matching. Not applicable — each feature type comes from a single source, so there is no matching step.

Merging. Not applicable — with a single source per feature type, there is no merging or conflation between sources.

Coverage and data quality​

Coverage. The base theme provides global coverage. Its features come directly from their source datasets — OpenStreetMap for land, water, and infrastructure, and dedicated global products for bathymetry and land cover.

Known quality issues. Because base features are translated directly from their sources with no conflation, their accuracy and completeness mirror the upstream data — primarily OpenStreetMap.

Release artifacts and updates​

The base theme is released on a monthly cadence. Alongside the data, the following release artifacts are provided:

  • GERS registry: Base features are not included in the GERS registry. Base is a single-source, pass-through theme with no matcher, so its features are not assigned registry IDs.
  • Data changelog: A changelog accompanies each release.
  • Bridge files: Not currently provided for the base theme.

Data access and retrieval​

Overture's base theme data is freely available on both Amazon S3 and Microsoft Azure Blob Storage at these locations:

providerlocation
Amazon S3
s3://overturemaps-us-west-2/release/2026-07-22.0/theme=base/type=bathymetry/*
Azure Blob Storage
https://overturemapswestus2.blob.core.windows.net/release/2026-07-22.0/theme=base/type=bathymetry/*

The Getting Started section of this documentation offers instructions for accessing the full Overture catalog.

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