[Geoserver-devel] GeoTools / GeoServer PMC meeting - 2024-08-13

GeoServer GeoServer Developer
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Attending- Torben Barsballe

  • Andrea Aime

  • Dave Blasby

  • Kevin Smith

Actions from prior meetings:- [Done] Jody: request or setup discourse channels (for screenshots)

  • Please help review PRs everyone!

Agenda- 2.24.5 and 2.26-RC releases managers

  • 2.26-RC incoming OMG!

  • Javascript/CSP/Wicket fun

  • TilematrixSet support in CSS and more

  • JDK 17 officially supported

  • Vector tiles chit chat

Actions- Volunteer for 2.26-RC

2.24.5 and 2.26-RC releases managers

Andrea to do 2.24.5 and 2.26-RC needs a release manager (see also mail communication).

2.24.5 last officially planned.

2.26-RC incoming OMG!

September 2nd final deadline for new features.

Some ideas:

Stuff too late to merge:

Javascript/CSP/Wicket fun

Some of the changes in the Wicket-9 upgrade produced CSP failures

These should now be fixed for homepage / WPS Request builder / WMS Request Builder

TilematrixSet support in CSS and more

Want to introduce Zoom level support into CSS to allow for writing vectorTile styles

YSLD has classes to support this already - ZoomContext, ZoomContextFinder, GWCZoomContextFinder. They are sufficiently generic to be trivial to bring up to gt-main.

GeoServer should be the only user of the classes, so this refactor shouldn’t cause dependency issues for users of GeoTools.

It would also be good practice to have YSLD (etc.) look-up GWC-related classes dynamically.

JDK 17 officially supported- Marlin integration issue solved, now starts and works with Java 17 and Java 21.

  • Depending on context/how it gets started, you might need to tweak the JVM options, adding “–add-opens” and friends. We have that documented.

  • Tomcat 9 deployment + Java 17 seems to work without needing tweaks

And also add Java 21 as experimental (actually GeoServer Cloud uses it by default).

### Vector tiles chit chat

Tile Size Improvement Discussion:

  • Filter attributes before tiles generation

  • Seperate label and rendering layers

  • Merge features that share all attributes

All of this configurable through the GUI

Example from OpenMapTiles (a tile from St. Luis, zoom level 14), this selection is “one MVT feature”, all the buildings sharing the same attributes are one multi-polygon:

This reduces MVT size tremendously (as well as browser-side rendering speed)

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Hi all,
I’ve been thinking about the attribute selection in vector tile production.
During the meeting I’ve shown its importance in keeping vector tiles small and how it enables merging multiple
features into one (the less attributes, the more likely that two features share the same values).

I also proposed to create a dedicated configuration section for vector tiles, in the layer publishing tab, to
select which attributes go into the vector tiles, and eventually which ones go into the label sidecar layer.
Thinking about it a bit more, I want to make that configurable in the style instead. Reasoning:

  • Keeps all the vector tile configuration in one bit (the style being already used for scale dependencies and feature filtering)
  • Allows to have different styles generate different types of vector tiles. One could have a simpler and a richer vector tile set. The style is also a WMTS/OGC API Tiles request parameter, which allows to tell apart the two tile sets.
  • Allows settings to be scale dependent (we might want more/less attributes depending on the scale, and also have the label sidecar layer only when zoomed in enough )
    With this in mind, the configurations would go into FeatureTypeStyle and Rule (FTS for general statements, Rule for scale dependent ones)…
    a style designed to drive VTs normally has one of each.

Even in the case of a style that plays both the role of server side rendering and VT driving, we could have the machinery pick the configuration
from the list active portions at the current scale denominator/zoom level (rendering tools already filter down a style based on the active rules,
eliminating the FTS that are left without any active rule). In case of conflict, I’d go for picking the union of the attributes.

The vendor options would be:

  • vt-attributes: comma separated list of attributes to include in the vector tile
  • vt-label: true/false, enables the creation of a separate label layer
  • vt-label-attributes: comma separated list of list of attributes to include in the label layer
    Here is an example of a CSS style used to drive the creation of a topp:states equivalent as MVT,

with the idea that the label sidecar layer will only be available after zoom level 4:

topp:states {
fill: black;
vt-attributes: ‘PERSONS’;
[@z >= 4] {
vt-label: true;
vt-label-attributes: ‘STATE_ABBR,STATE_NAME’; // in case we want to display full name when zoomed in
}
}

Thoughts?

···

Regards,

Andrea Aime

==
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Ing. Andrea Aime
@geowolf
Technical Lead

GeoSolutions Group
phone: +39 0584 962313

fax: +39 0584 1660272

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https://www.geosolutionsgroup.com/

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2.26-RC incoming OMG!

September 2nd final deadline for new features.

Some ideas:

Stuff too late to merge:

It looks like David and Michel started on the A/B testing see: https://github.com/geoserver/geoserver/pull/7154

Let me have a go at setting up the automation; as it is non functional any changes do not affect the RC schedule.