Working Group Minutes/EWG 2023-11-29

From OpenStreetMap Foundation

Formal proceedings


  • Andrew Hain
  • Adam Hoyle
  • Tobias Knerr
  • Roland Olbricht
  • Emerson Rocha


  • Paul Norman


  • Salim Baidoun

Actual business

Vector Tiles

The EWG reviews Paul Norman's Vector Tiles proposal.

Adam had a good discussion at the end of SOTM about Vector Tiles with Paul Norman and Guillaume (Sarah Hoffman and Amanda McCann were also present at some points). The primary thing to note for EWG is that:

  • Paul will submit his proposal to EWG and we will approve it and use our budget to fund it.
  • Any additional money we will need above and beyond our current budget will be added to the budget request for 2024 that we will be putting together soon.
  • The EWG supplies the Communications Working Group (CWG) to produce at least 2 blog posts, an initial one to say the work is starting and one when it is in production.
  • There should be a competition or Micro-grants or something to encourage the community to create map styles using shortbread.

This latter one is not in Paul's scope and not something to dive in straight away. It would be an EWG initiative, perhaps with CWG support.

Discussion about the Vector Tiles proposal

EWG members discuss some questions on the proposal with Paul.

Topics include:

How long does it take to reload the database in case the schema must be changed: well under 24 hours, making it possible to do so every now and then without disrupting the tiles service.

Use of Shortbread: the selection of tags to include is up to the authors of the Shortbread spec, and these are separate from the tooling which is included in this proposal. Not everything is available in the tiles and this is intentional and understood for the taken approach.

The problems with the mechanism to figure out "dirty" tiles are an effect of changes to relations, and most such requests in the raster tile world came anyway from unrelated problems. This is both unrelated to vector tiles and, as said, of lower relevance than perceived. The zoom-dependent tile expiry might even improve the rendering lag. Replacing outdated tiles with a regular browser refresh is also unrelated and out of scope.

A side remark to raster tiles: Mapnik as a software is basically abandoned. It is possible, to enhance the vector tile stack with a raster tile extension to serve raster tiles as a last resort for incompatible devices.

Manipulating projections on the fly is possible. However, there are caveats in the polar region, see MapLibre. Is the tooling able to be ported to a different tiling scheme to avoid limitations for polar maps? This is expected to be difficult, the assumption that the output is XYZ tiles is quite deeply ingrained in the code and not easily refactored.

Paul and the EWG agree that a community demo shall be in the first milestone to make to ongoing work as visible as possible to the community.

Paul would prefer to invoice monthly. Paul expects to work on average 25 to 30 hrs per week.

Motion: The EWG approves the proposal subject to the contract with Paul. All members of the EWG in this meeting approve.

The EWG does not have a contract template and is not aware that a contract template exists elsewhere within the OSM Foundation. The EWG asks Paul to suggest a contract template based on the last contract over two days of consulting.

Status of Mute Users feature

Emerson promises to an eye on relevant activity (issues etc.) and to report to EWG about Gregory progress (on the main issue for the mute users feature).

Topic deferred due to overdraft meeting time.

Refactoring of OSM website notes

Tobias has merged the pull request for a second bidding project according to the vote at the last meeting. There has been some discussion on this pull request there after that.

Roland volunteers to write a blog post for the Communications Working Group to promote for the second bidding project potential bids. It shall also advertise the accomplished work on the first RFP.

Scheduled for this meeting: Advertise the bid on the Community Forum and other channels.

Budget planning

The EWG starts to reflect about its budget request for 2024. Things known already:

  • Paul's work
  • Microgrants: We plan with 30 000 EUR based on half the size of the first round, because it is only for technology projects. There shall be a ceiling of 6000 EUR per project, lifted from 5000 EUR of 2020 to account for inflation.
  • Costs for "Refactoring OSM website notes" and "GDPR"
  • and 1 or 2 other future website improvements

Future Projects


Salim will send email on the progress with grants to EWG.

For convenience: Announcement of the awarded bids, list of projects.

It is discussed to increase the maximum award from 5k to 6k EUR to compensate for inflation. Several tech projects in 2020 were additionally funded directly by board decision rather than from the microgrant budgets. Paul remarks that the goal is a mix of interesting (more risky) projects and boring/safe work to ensure ultimately some results are available and some known longstanding problems solved.

Any other business

Next meeting

Next meeting is 2023-12-13, 16:30 UTC