The Open Geospatial Consortium (OGC) is excited to announce the formation of the OGC GeoZarr Standards Working Group (SWG). The new SWG will develop a Zarr encoding for geospatial gridded data in the form of Zarr conventions.

Zarr is a cloud-native data format for n-dimensional arrays that enables access to data in compressed chunks of the original array. Zarr facilitates portability and interoperability on both object stores and hard disks. 

As a generic data format, Zarr has increasingly become popular to use for geospatial purposes. As such, in June 2022, OGC endorsed Zarr V2.0 as an OGC Community Standard. The purpose of the GeoZarr SWG is to have an explicitly geospatial Zarr Standard (GeoZarr) adopted by OGC that establishes flexible and inclusive conventions for the Zarr cloud-native format that meet the diverse requirements of the geospatial domain. These conventions aim to provide a clear and standardized framework for organizing and describing data that ensures unambiguous representation.

The objectives of GeoZarr conventions include:

  1. Compatibility: Ensuring easy compatibility with popular mapping and data analysis tools such as GDAL, Xarray, ArcGIS, QGIS, and other visualization tools, enabling seamless integration into existing workflows.
  2. Dimensions: Supporting multi-dimensional data, such as hyperspectral and altitude information, to address diverse geospatial data requirements.
  3. Data Discovery: Providing metadata for discovering, accessing, and retrieving the data, including composite products made of multiple data arrays.
  4. Mixing Data: Facilitating the combination of different types of geospatial data, including satellite images, elevation maps, and weather models, to create comprehensive and informative datasets.
  5. Flexibility: Allowing scientists and researchers to work with diverse data types and projections in their preferred software and programming languages, promoting flexibility and adaptability in geospatial data processing and analysis.

In addition to the encoding of geospatial data and metadata, the GeoZarr Standard will provide a multi-dimensional alternative to the two-dimensional Cloud-Optimized GeoTiff format (COG – adopted by OGC in May 2023), which has lately gained popularity due to its serverless capabilities. These capabilities will allow for inherent support of traditionally server-based functions, such as visualization (similar to OGC API – Maps), data subset access (analogous to OGC API – Coverages), and symbology (equivalent to OGC API – Styles). These aspects are planned to be incorporated as optional profiles (e.g. conformance classes).

OGC Members interested in staying up to date on the progress of this standard, or contributing to its development, are encouraged to join the GeoZarr Standards Working Group via the OGC Portal. Non-OGC members who would like to know more about participating in this SWG are encouraged to contact the OGC Standards Program.


Cloud Native, GeoZarr, SWG, Zarr