New feature proposal: <(map)> and <layer> elements

[prushforth]

Hi there, we (the Maps for HTML CG) want to share our ideas with the WHATWG community, and it has been suggested that opening an issue here might help facilitate the process of getting feedback on these ideas for an extension to the Web Platform. Such an extension might result in the requirement to add and / or extend some parts of HTML, along the lines of the subject of this issue.

We recently published a report from our 2020 Workshop, which brought together mapping stakeholders from around the world, and it's worth reading the executive summary and perhaps more of it if you're interested (the quotes are particularly important). The conclusion of the workshop community is that we should pursue incremental standardization and implementation of maps and location in the Web Platform, starting by defining what the primitives that we need are.

The workshop participants uncovered a number of pain points for Web mappers:

• the accessibility of Web maps is not standardized, leaving disabled users with widely variable experiences and utilities
• good Web map performance is extremely difficult to achieve and is relatively unsupported by browsers. Having "good performance" built in will allow our community to focus less on client rendering and contribute more to the Web Platform.
• Web map internationalization does not yet benefit from the huge efforts that have been invested by browsers in international text rendering (because map rendering is script-centric)
• CSS is not yet directly relevant to Web mapping since there's no platform-standard way to represent maps and map features (i.e. roads, sidewalks etc.).
• 2D Web maps that represent real-world coordinates are on the spectrum of features leading to Augmented Reality. Start simple, and useful!

Our community has been iterating on Use Cases and Requirements, the "MapML" proposal (map semantics in HTML) and custom element polyfills. We are tracking our progress through the UCR Fulfillment Matrix, which relates the UCR and various Web map implementations, with the objective that we are able to eventually define a complete set of requirements together with a coherent and acceptable proposal (specification) on how to incrementally implement those requirements.

Request for Feedback

Our community group invites feedback from WHATWG members on the process, documents and results that have been developed so far. Specifically, are we aligned on the use cases? We would also like to collaborate with browser developers so that some platform use cases that are particularly important to map rendering don't leave maps out of scope, for example zoom and pan, which seems to be a cross-cutting capability that could greatly apply to maps if taken into account.

It's our intention to further engage with the mapping, accessibility and browser developer communities. We have seen evidence of openness to pursue standardization from some important mapping and accessibility stakeholders and we would like to engage with the browser development community through this issue.

[zcorpan]

"Maps for HTML CG" could link to https://www.w3.org/community/maps4html/

The request for feedback I think could have a more specific ask, like: Are we aligned on the use cases?

Other than that, looks good to me.

[Malvoz]

• CSS is not yet directly relevant to Web mapping since there's no platform-standard way to represent maps and map features (i.e. roads, sidewalks etc.).

Since this is talking about missing CSS primitives, should we take the opportunity to link to the "per-element panning and zooming" CSSWG issue that @zcorpan raised?

[prushforth]

Submitted - locked this issue - please comment over there.