Google Open Buildings: Building Footprints for GIS, Earth Observation, and Spatial Analysis

Google Open Buildings is an open geospatial dataset of machine-detected building footprints derived from high-resolution satellite imagery. The principal V3 polygons release contains approximately 1.8 billion building detections across Africa, Latin America, the Caribbean, South Asia, and Southeast Asia, covering an inference area of about 58 million square kilometres. Each record provides a building polygon, estimated area, model confidence score, centroid coordinates, and a Plus Code. The dataset is useful for building-density analysis, settlement mapping, population estimation, humanitarian planning, environmental studies, and creating building layers where authoritative local data is unavailable. It does not provide building names, addresses, land use, occupancy, height, construction date, ownership, or a guaranteed complete inventory of structures. The public documentation identifies the V3 inference as having been carried out in May 2023 and does not specify a fixed recurring update cadence. (developers.google.com)

Google Open Buildings is designed for a problem that many GIS teams encounter outside well-mapped, data-rich regions: satellite imagery may show extensive built development, but a consistent, reusable building-footprint layer may not exist. Google Research used machine learning to infer building outlines from high-resolution satellite imagery and released the results as an open dataset. The result is a large vector layer that can be downloaded by spatial tile, explored visually, loaded into Google Earth Engine, or incorporated into a conventional GIS workflow. (sites.research.google) The dataset is best understood as an inferred observation layer rather than a legal or authoritative building register. It answers questions such as “where are likely building structures?” and “how much building footprint falls inside this area?” It does not, by itself, answer who owns a building, what it is used for, whether it is occupied, or which postal address corresponds to it. That distinction matters when combining Open Buildings with roads, administrative boundaries, population estimates, imagery, environmental layers, or public-service data.

How EDK fits

For: GIS analysts, remote-sensing researchers, humanitarian and development organizations, urban planners, open-mapping contributors, data engineers, and developers who need broad building-footprint coverage for regions where local building datasets are incomplete or difficult to obtain.

Open Buildings is a concrete example of how a physical-world data layer becomes useful when it can be searched, joined, measured, and compared with other geographic features. A building footprint is not merely a polygon on a map: it is an observable representation of the built environment that can support questions about settlement extent, service access, exposure, infrastructure demand, and change over space. In an E2-oriented workflow, the dataset can serve as one building-evidence layer within a broader world model that also includes roads, addresses, public assets, environmental features, imagery, and administrative geography. The important editorial distinction is that Open Buildings supplies inferred building geometry and related confidence information; it does not itself provide the rest of that world model. The dataset is especially relevant to computation about the physical world because its geometries can be aggregated, filtered, ranked, intersected, and compared. Analysts can count or sum building area inside a region, estimate building density near roads or services, identify areas with sparse mapped infrastructure but substantial built coverage, or use confidence thresholds to create application-specific subsets. In an E2 context, two suitable use cases are: 1. **Building-density and service-access analysis:** combine Open Buildings footprints with roads, schools, clinics, water features, transit stops, or public-service records to measure how built-up areas relate to access and infrastructure coverage. The external dataset contributes building geometry; other layers are required for the service and network questions. 2. **Regional built-environment screening:** aggregate footprint count and area by grid cell, administrative unit, watershed, or custom region, then compare the results with imagery, population, environmental hazards, or construction-related observations. Confidence filtering and local validation remain necessary before treating the results as decision-grade inventory.

  • •Measure and compare building counts, footprint area, and building density across neighborhoods, administrative areas, service zones, watersheds, or custom analysis grids.
  • •Use building footprints as one physical-world layer alongside roads, public assets, environmental features, imagery, and demographic data to study service access, settlement expansion, infrastructure demand, or hazard exposure.
  • •Filter detections by confidence and spatially intersect them with other geographic features to identify areas requiring local mapping, validation, or more detailed building surveys.
Dataset
Google Open Buildings V3 Polygons
Primary feature type
Inferred building footprint polygons, with related point and threshold files
Documented coverage
Africa, Latin America, the Caribbean, South Asia, and Southeast Asia; approximately 58 million square kilometres of inference area
Approximate scale
About 1.8 billion building detections
Imagery basis
High-resolution 50-centimetre satellite imagery
Inference period
May 2023 for V3 polygons

Dataset profile

license
The official project documentation describes dual availability under CC BY 4.0 and ODbL 1.0. The Google Earth Engine catalog lists CC BY 4.0 for the V3 asset. Review the applicable terms for the access and redistribution method used.
geography
Documented V3 coverage spans Africa, Latin America, the Caribbean, South Asia, and Southeast Asia. Coverage is not necessarily complete within every listed region; verify the precise country, city, or S2 cell in the official explorer.
resolution
Vector building footprints inferred from high-resolution 50-centimetre satellite imagery. The dataset does not provide a single uniform positional-accuracy guarantee for every footprint.
update cadence
No fixed recurring update cadence was identified in the official documentation. Version history and inference dates should be recorded for each use.
temporal coverage
V3 polygon inference was carried out in May 2023. This is a dated inferred building layer, not a continuous time series. Related Open Buildings products may have different temporal structures and should not be conflated with V3 polygons.

Formats

Spatially sharded CSV files organized by S2 level-4 cells.

WKT POLYGON or MULTIPOLYGON geometry for building footprints.

CSV building-point files with centroid and related attributes.

CSV score-threshold file with cell-level confidence and precision estimates.

Google Earth Engine FeatureCollection asset for V3 polygons.

Plus Codes for building polygon centroids.

Access methods

Download selected spatial shards through the official Open Buildings explorer.

Use the official Colab workflow to download data for a country or region.

Load the V3 FeatureCollection in Google Earth Engine using the catalog asset identifier.

Use the project explorer for visual coverage inspection and manual selection.

Build a local or cloud pipeline from the CSV shards after recording version, cells, and retrieval date.

Quality and limits

The layer is machine-generated and may contain false detections or inaccurate polygon shapes.

Imagery may be incomplete, outdated, cloud-obscured, or unable to reveal some buildings.

Buildings can appear offset relative to currently displayed imagery when source imagery dates differ. (sites.research.google)

Coverage is not guaranteed to be complete across the broad regions listed by the project.

Confidence scores are not equivalent to legal certainty or a universal probability of correctness.

The dataset does not provide building type, address, height, occupancy, ownership, or construction status.

The V3 release is dated to May 2023 and has no documented recurring update schedule.

High-stakes or operational uses require comparison with current imagery, local mapping, or authoritative local records.

Analysis workflows

Coverage audit: inspect the official explorer, identify included S2 cells, and record the dataset version and inference date.

Ingestion: parse CSV and WKT geometry, preserve source attributes, validate geometries, and convert to a spatial format such as GeoPackage or spatial Parquet.

Confidence analysis: inspect local score distributions and apply a fixed or cell-specific threshold appropriate to the intended precision-recall tradeoff.

Regional aggregation: calculate building counts, total footprint area, density, size distributions, and change or comparison statistics by grid, boundary, watershed, or service area.

Spatial integration: intersect footprints with roads, public assets, environmental layers, hazards, population estimates, imagery, or administrative boundaries.

Validation: sample detections across density classes and confidence ranges, compare against recent imagery or local reference data, and quantify omission and commission errors where possible.

Reproducibility: preserve source shards, retrieval date, filters, threshold logic, geometry-processing steps, license notices, and output version identifiers.

Value inside EDK

What Google Open Buildings contains

The core V3 polygons dataset represents building footprints inferred from 50-centimetre satellite imagery. Google reports approximately 1.8 billion building detections across Africa, Latin America, the Caribbean, South Asia, and Southeast Asia, with inference spanning roughly 58 million square kilometres. Each polygon describes the estimated ground footprint of a detected structure. (developers.google.com)

The principal attributes are deliberately limited. A record includes polygon geometry, area in square metres, a confidence score ranging from 0.65 to 1.0 in the published dataset, centroid longitude and latitude, and a full Plus Code for the centroid. The dataset does not identify whether a structure is residential, commercial, industrial, religious, educational, informal, abandoned, or under construction. It also does not provide a street address or a complete building-level description. (developers.google.com)

  • •Building polygons for footprint-based GIS analysis.
  • •Building points representing detected building locations or centroids.
  • •Area and confidence attributes for filtering and aggregation.
  • •Plus Codes that provide a location reference for each detected building centroid.
  • •S2-cell score-threshold information for confidence and precision analysis.

Geography, temporal coverage, and update cadence

Open Buildings V3 is not a uniform global building inventory. Its documented coverage includes Africa, Latin America, the Caribbean, South Asia, and Southeast Asia, and the project notes that imagery was not processed for every location within those broad regions. The official explorer should be used to check whether a particular country, city, or area is included before designing an analysis around it. (developers.google.com)

For V3 polygons, Google identifies May 2023 as the inference period. The Earth Engine catalog records the asset availability date as May 30, 2023, but that is not the same as a continuous monitoring period or a guarantee that every footprint reflects conditions on that date. The dataset should therefore be treated as a dated extraction of inferred building presence, not as a live building-change service. (developers.google.com)

  • •Broad regional coverage, but not guaranteed complete coverage within every listed region.
  • •V3 polygon inference period: May 2023.
  • •No documented recurring update schedule was found in the cited official materials.
  • •Version and imagery-date checks are necessary for temporal comparison.

Formats and access methods

The project website provides spatially sharded CSV files, organized using S2 level-4 cells. Polygon files contain latitude, longitude, area, confidence, WKT geometry, and a full Plus Code. The official site reports approximately 178 GB for the polygon data and approximately 48 GB for the point data, with individual shard sizes varying substantially. (sites.research.google)

Users can download data for selected cells or use the project’s country- and region-oriented Colab workflow. The dataset is also available as a Google Earth Engine FeatureCollection under the asset identifier shown in the Earth Engine catalog. The Earth Engine route is convenient for filtering, mapping, and regional computation without first assembling all raw CSV shards locally, although Earth Engine account, quota, export, and platform-use conditions still apply. (developers.google.com)

  • •Spatially sharded CSV files for polygons and points.
  • •WKT polygon or multipolygon geometry in the raw polygon files.
  • •Google Earth Engine FeatureCollection access.
  • •Interactive explorer for coverage inspection and selected downloads.
  • •Colab-based workflow for country or regional extraction.

Suitable GIS and spatial-analysis workflows

A defensible workflow begins with coverage validation. Confirm that the area of interest is represented in the explorer or selected S2 cells, then preserve the original records and metadata before transforming the data. Because the raw files are distributed as CSV with WKT geometry, a common process is to parse the geometry into a spatial data frame, validate polygon shapes, assign the intended geographic reference system, and convert the result to GeoPackage, Parquet, a spatial database, or another analysis-ready format.

For exploratory mapping, symbolize confidence as a graduated attribute and inspect the distribution of footprint sizes. For regional summaries, calculate building counts, total footprint area, median or quantile footprint size, and density per square kilometre inside a consistent grid or boundary layer. For service-access studies, intersect the footprints with catchments, buffers, road networks, schools, health facilities, or other public assets. For environmental analysis, overlay them with flood zones, surface water, terrain, land cover, or protected areas, while remembering that the building layer may reflect a different image date and positional accuracy than the comparison data.

  • •Validate geographic coverage before downloading or modeling.
  • •Parse WKT carefully and preserve the original confidence and area fields.
  • •Use confidence thresholds appropriate to the geographic cell and application.
  • •Aggregate counts and footprint area only after defining a consistent analysis unit.
  • •Compare with imagery or local data before treating detections as confirmed structures.
  • •Record version, inference date, source cells, filters, and processing decisions for reproducibility.

License, strengths, and tradeoffs

The official Open Buildings project states that the data is available under both the Creative Commons Attribution 4.0 license and the Open Database License 1.0, allowing users to choose the license that fits their use while following its terms and attribution requirements. The Earth Engine catalog identifies the V3 catalog asset as CC BY 4.0. Because licensing can depend on how data is accessed, transformed, and redistributed, teams should review the official terms before publishing a derivative database or incorporating the layer into a commercial product. (sites.research.google)

The principal strength is scale: Open Buildings provides a consistent building-footprint starting point across regions where local GIS layers may be fragmented. Its machine-readable geometry and confidence information make it suitable for spatial aggregation, screening, and integration with other geospatial data. Its principal tradeoff is that scale and inferred coverage do not eliminate uncertainty. Missing imagery, cloud cover, dated imagery, false positives, inaccurate boundaries, and regional variation in model performance can all affect results. (sites.research.google)

  • •Strength: very large regional coverage and a consistent machine-readable structure.
  • •Strength: useful footprint, area, confidence, centroid, and Plus Code attributes.
  • •Strength: multiple access paths, including raw CSV, explorer, Colab, and Earth Engine.
  • •Tradeoff: not a global or necessarily complete building inventory.
  • •Tradeoff: no building type, address, height, ownership, occupancy, or use attributes.
  • •Tradeoff: dated inference and uncertain update cadence limit real-time or change-monitoring use.
  • •Tradeoff: model errors and imagery limitations require validation for high-stakes decisions.

Questions teams ask

Is Google Open Buildings a complete global building dataset?

No. The documented V3 coverage includes Africa, Latin America, the Caribbean, South Asia, and Southeast Asia, but processing is not complete across every location in those regions. The project explorer should be used to confirm coverage for a specific area. It is also an inferred dataset, so mapped coverage should not be interpreted as a guaranteed inventory of every structure. (developers.google.com)

What attributes does each Google Open Buildings polygon contain?

The published polygon data includes WKT geometry, estimated area in square metres, a model confidence score, centroid latitude and longitude, and a full Plus Code. It does not provide a street address, building type, ownership, occupancy, height, or other detailed building semantics. (developers.google.com)

How current is Google Open Buildings?

The V3 polygon inference was carried out in May 2023. The official materials reviewed here do not state a fixed recurring update cadence. The dataset should therefore be treated as a dated release, and current applications should compare it with newer imagery or local data where recency matters. (developers.google.com)

Can Google Open Buildings data be used in OpenStreetMap?

The project documentation says that the buildings can be added to OpenStreetMap, but recommends human review, local knowledge, and filtering out lower-confidence detections before import. Machine-generated geometry should not be treated as automatically correct. (sites.research.google)

What is the best confidence threshold to use?

There is no single threshold that is guaranteed to be best for every location or purpose. Google provides cell-level estimates for thresholds associated with 80%, 85%, and 90% precision. Analysts should select and document a threshold based on the application, inspect local results, and validate important areas against imagery or local reference data. (sites.research.google)

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