The Open Geospatial Consortium (OGC) is excited to announce that the OGC Membership has approved Version 1.0 of the Common Query Language (CQL2) for adoption as an official OGC Standard.
Filtering is a fundamental operation performed on feature data to obtain a subset that contains the geospatial information a user needs. CQL2 is a filter grammar that can be used to specify how features can be filtered to obtain a subset. The Standard supports both text and JSON encodings so can be easily integrated into a variety of software applications.
CQL2 is a revision of the original Common Query Language. While the language design is consistent with the original version, many changes and additions to improve consistency and capabilities have been made. Existing implementations of CQL will need to be updated to process filter expressions specified by CQL2.
The OGC API – Features Standard currently uses CQL2, and other Standards that require the ability to filter data are likely to adopt it as well. Example files and JSON, YAML, and BNF schemas have been published on the OGC schemas repository to enable software developers to rapidly implement CQL2.
The original Common Query Language (CQL) was created as a text encoding for use in the OGC Catalogue Service Implementation Specification. CQL is based on the capabilities in the OGC Filter Encoding (FE) Standard, which was originally part of the Web Feature Service (WFS) Standard.
CQL2 is the outcome of the work and dedication of the OGC API – Features Standards Working Group, which led the development of the Standard, including:
- Editors:
- Panagiotis (Peter) A. Vretanos, CubeWerx Inc.
- Clemens Portele, interactive instruments GmbH
- Submitters:
- Andrea Aime, GeoSolutions di Giannecchini Simone & C. s.a.s.
- Jeff Harrison, US Army Geospatial Center (AGC)
- Jérôme Jacovella-St-Louis, Ecere Corporation
As with any OGC Standard, CQL2 is free to download and implement. Interested parties can learn more on the OGC CQL2 Standard webpage.