FOSS4G 2023

Overview of draft OGC Styles & Symbology "SymCore" 2.0 models & encodings
06-28, 16:00–16:30 (Europe/Tirane), UBT D / N112 - Second Floor

An overview of the Core Models and Encodings for Styling and Symbology - Part 1: Core ("SymCore") 2.0 draft candidate Standard.

In comparison to the current OGC Symbology Conceptual Model: Core Part ("SymCore") version 1.0, the new draft candidate Standard aims to better reflect its classification as an OGC Implementation Standard by including the requirements classes needed to enable the implementation of interoperable encodings, renderers (e.g., OGC API - Maps / OGC API - Tiles) and systems parsing and/or generating style definitions (e.g., OGC API - Styles, visual style editors, style transcoders).

It does so by featuring:

  • A modular logical and conceptual model for styling capabilities,
  • A minimal Core requirements class including clear extension mechanisms, through the definition of abstract Selectors, Symbolizers, and Expressions,
  • a basic Vector Styling requirements class,
  • a basic Coverage Styling requirements class,
  • requirements classes providing additional styling functionality,
  • a JSON encoding of the conceptual and logical model facilitating machine readability,
  • a CSS-inspired encoding of the conceptual and logical model facilating hand-editing.

The latest version of the draft is available in HTML ( or PDF (

The official GitHub repository is at:

Jérôme is founder and CTO of Ecere, designed the eC programming language, initiated the FOSS Ecere Cross-Platform SDK and GNOSIS geospatial software. Jérôme is an OSGeo charter member, co-chair of the Ottawa Local Chapter, OGC Styles & Symbology, OGC API – Tiles and OGC API - Coverages Standard Working Groups.

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