Jody Garnett (GeoCat) is proposing this activity to better support our GeoCat Bridge customers and the combination of GeoServer and Vector Tiles.

Note this proposal uses "MBStyle" to avoid making use of MapBox trademark.

This proposal is for GeoServer 2.17-RC1, see GEOS-9523

• Under Discussion
• In Progress
• Completed
• Rejected
• Deferred

The Vector Tile extension for GeoServer is a popular way to generate tiles for use in MapBox.GL or OpenLayers.

The MBStyle extension is a great addition to this workflow, enabling the same styling for both client side and server side.

Preflight check:

0. Proposal to GeoTools PMC to take mbstyle unsupported module to plugin status.

   • Double check the duplication between GeoTools and GeoServer "specification" documentation.

     GeoTools specification was the same
     

   • GEOT-6493 - MBStyle extension and pull-request

   • Fix tests and measure test coverage

Proposal covers:

1. Moving the module from community to extension in the build system.

2. Updating the website template to make the extension available.

3. Updating the pom.xml contract information.

4. Updating documentation for this extension:

   • Remove removing duplication of specification, provide a link to GeoTools docs
   • Maintain Reference Manual in GeoServer

5. Updating the release packaging

The Mapbox Style Specification is quite active ("unstable" by design). During life as a community module we have seen expression support added (deprecating filter in the process). Staying "current" is likely to require ongoing effort, interest and investment.

On the positive side the standard is documented with these concerns in mind, each feature being marked as available in Mapbox GL JS, Android SDK, iOS SDK, or macOS SDK. Our own copy of the documentation reflects this approach indicating what capabilities are supported.

The standard is "open specification" in that it is freely available to read. Stepping back it is of concern that the standard is now formally part of Mapbox GL JS documentation (and no longer maintained neutral to a specific SDK). MapBox spec is no longer standalone and subject to weekly updates. This tends to imply the standard will change more over time, and become more of a "boutique" document over time as it aligns with the needs of a specific library.

The developers guide lists several requirements for community modules graduating to an extension:

1. The module has at least a “handful” of users

   • It was include in Boundless Suite, not sure how many users?
   • GeoCat is committed to supporting our customers use of this module, but wishes to see the functionaly incorporated into core or set up as an extension first.

2. The module has a designated and active maintainer

   • Jody Garnett (GeoCat) is willing to act in this capacity

   • Torben is available as co-maintainer

3. The module is considered “stable” by the majority of the PSC

   • The module been working for several releases, recently the underlying GeoTools implementation has seen a host of fixes and improvements.

4. The module maintains 40% test coverage

   • Coverage of 87% reported by Andrea

5. The module has no IP violations

   • This community module was developed by Boundless from the start and is covered under their CLA.

   • The documentation contains a duplication of the mapbox style specification to document the capabilities of our implementation. This is within the BSD license terms of MapBox GL client.

6. The module has a page in the user manual

   • Requirement noted in proposal plan. Intend to have reference material and a couple of examples.

7. The maintainer has signed the GeoServer Contributor Agreement

   • Jody Garnett and GeoCat have signed OSGeo CLA, GeoServer Contributor Agreement no longer used.

Additional graduation considerations:

8. User interface review

   • The style editor is already shown to be compatible with this additional style format. Indeed the style editor "group mode" was setup with this format in mind.

9. REST API review

   • The REST API endpoint is already shown to be compatible with this additional style format.

10. Security considerations

• The MBStyle is eventually processed into normal GeoTools Style data structures. No additional security vulnerabilities are expected as we are avoiding a lot of XML parsing.

Project Steering Committee:

• Alessio Fabiani:
• Andrea Aime: +1
• Ian Turton:
• Jody Garnett: +1
• Jukka Rahkonen: +1
• Kevin Smith:
• Simone Giannecchini:
• Torben Barsballe: +1
• Nuno Oliveira: +1

• GEOS-9523
• https://github.com/geoserver/geoserver/pull/4098
• Style Specification (Mapbox GL JS)
• Mapbox Style Specification (GeoTools User Manual)
• Mapbox Style Specification (GeoServer User Guide)
• MBStyle Styling (User Guide)
• MBStyle Styling Workbook
• GeoTools / GeoServer Meeting 2019-03-01